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fetchmail(1)		  fetchmail reference manual		  fetchmail(1)

NAME
       fetchmail - fetch mail from a POP, IMAP,	ETRN, or ODMR-capable server

SYNOPSIS
       fetchmail [option...] [mailserver...]
       fetchmailconf

DESCRIPTION
       fetchmail  is  a	mail-retrieval and forwarding utility; it fetches mail
       from remote mailservers and forwards it	to  your  local	 (client)  ma-
       chine's	delivery system.  You can then handle the retrieved mail using
       normal mail user	agents such as mutt(1),	elm(1) or Mail(1).  The	fetch-
       mail utility can	be run in a daemon mode	to repeatedly poll one or more
       systems at a specified interval.

       The fetchmail program can gather	mail from servers  supporting  any  of
       the  common  mail-retrieval protocols: POP2 (legacy, to be removed from
       future release),	POP3, IMAP2bis,	IMAP4, and IMAP4rev1.  It can also use
       the ESMTP ETRN extension	and ODMR.  (The	RFCs describing	all these pro-
       tocols are listed at the	end of this manual page.)

       While fetchmail is primarily intended to	be used	over on-demand	TCP/IP
       links  (such  as	 SLIP  or PPP connections), it may also	be useful as a
       message transfer	agent for sites	which refuse for security  reasons  to
       permit (sender-initiated) SMTP transactions with	sendmail.

   SUPPORT, TROUBLESHOOTING
       For troubleshooting, tracing and	debugging, you need to increase	fetch-
       mail's verbosity	to actually see	what happens. To do that,  please  run
       both  of	 the  two  following commands, adding all of the options you'd
       normally	use.

	      env LC_ALL=C fetchmail -V	-v --nodetach --nosyslog

	      (This command line prints	in English how	fetchmail  understands
	      your configuration.)

	      env LC_ALL=C fetchmail -vvv  --nodetach --nosyslog

	      (This  command line actually runs	fetchmail with verbose English
	      output.)

       Also see	item #G3 in fetchmail's	FAQ <https://fetchmail.sourceforge.io/
       fetchmail-FAQ.html#G3>

       You  can	 omit  the LC_ALL=C part above if you want output in the local
       language	(if supported).	However	if you are posting to  mailing	lists,
       please  leave it	in. The	maintainers do not necessarily understand your
       language, please	use English.

   CONCEPTS
       If fetchmail is used with a POP or an IMAP server (but not with ETRN or
       ODMR),  it has two fundamental modes of operation for each user account
       from which it retrieves mail: singledrop- and multidrop-mode.

       In singledrop-mode,
	      fetchmail	assumes	that all messages in the user's	account	(mail-
	      box)  are	 intended for a	single recipient.  The identity	of the
	      recipient	will either default to the local user  currently  exe-
	      cuting fetchmail,	or will	need to	be explicitly specified	in the
	      configuration file.

	      fetchmail	uses singledrop-mode when the  fetchmailrc  configura-
	      tion  contains  at  most a single	local user specification for a
	      given server account.

       In multidrop-mode,
	      fetchmail	assumes	that the mail server account actually contains
	      mail  intended  for  any number of different recipients.	There-
	      fore, fetchmail must attempt to deduce the proper	"envelope  re-
	      cipient" from the	mail headers of	each message.  In this mode of
	      operation, fetchmail almost  resembles  a	 mail  transfer	 agent
	      (MTA).

	      Note  that  neither the POP nor IMAP protocols were intended for
	      use in this fashion, and hence envelope information is often not
	      directly	available.   The ISP must stores the envelope informa-
	      tion in some message header and. The ISP	must  also  store  one
	      copy  of	the message per	recipient. If either of	the conditions
	      is not fulfilled,	this process is	unreliable, because  fetchmail
	      must then	resort to guessing the true envelope recipient(s) of a
	      message. This usually fails for mailing list messages and	 Bcc:d
	      mail, or mail for	multiple recipients in your domain.

	      fetchmail	 uses  multidrop-mode  when  more  than	one local user
	      and/or a wildcard	is specified for a particular  server  account
	      in the configuration file.

       In ETRN and ODMR	modes,
	      these  considerations do not apply, as these protocols are based
	      on SMTP, which provides explicit envelope	recipient information.
	      These protocols always support multiple recipients.

       As  each	 message is retrieved, fetchmail normally delivers it via SMTP
       to port 25 on the machine it is running on (localhost), just as	though
       it  were	being passed in	over a normal TCP/IP link.  fetchmail provides
       the SMTP	server with an envelope	recipient derived in  the  manner  de-
       scribed	previously.  The mail will then	be delivered according to your
       MTA's rules (the	Mail Transfer Agent is usually	sendmail(8),  exim(8),
       or  postfix(8)).	  Invoking  your system's MDA (Mail Delivery Agent) is
       the duty	of your	MTA.  All the  delivery-control	 mechanisms  (such  as
       .forward	 files)	 normally  available through your system MTA and local
       delivery	agents will therefore be applied as usual.

       If your fetchmail configuration sets a local MDA	 (see  the  --mda  op-
       tion), it will be used directly instead of talking SMTP to port 25.

       If  the	program	fetchmailconf is available, it will assist you in set-
       ting up and editing a fetchmailrc configuration.	 It runs under	the  X
       window  system and requires that	the language Python and	the Tk toolkit
       (with Python bindings) be present on your system.   If  you  are	 first
       setting	up  fetchmail for single-user mode, it is recommended that you
       use Novice mode.	 Expert	mode provides complete	control	 of  fetchmail
       configuration,  including  the multidrop	features.  In either case, the
       'Autoprobe' button will tell you	the  most  capable  protocol  a	 given
       mailserver  supports,  and  warn	 you  of  potential problems with that
       server.

GENERAL	OPERATION
       The behavior of fetchmail is controlled by command-line options	and  a
       run  control file, ~/.fetchmailrc, the syntax of	which we describe in a
       later section (this file	is  what  the  fetchmailconf  program  edits).
       Command-line options override ~/.fetchmailrc declarations.

       Each  server name that you specify following the	options	on the command
       line will be queried.  If you do	not specify any	servers	on the command
       line,  each  'poll'  entry in your ~/.fetchmailrc file will be queried,
       unless the idle option is used, which see.

       To facilitate the use of	fetchmail in scripts and pipelines, it returns
       an appropriate exit code	upon termination -- see	EXIT CODES below.

       The  following  options modify the behavior of fetchmail.  It is	seldom
       necessary to specify any	of these once you have a working  .fetchmailrc
       file set	up.

       Almost  all  options  have a corresponding keyword which	can be used to
       declare them in a .fetchmailrc file.

       Some special options are	not covered here, but are  documented  instead
       in sections on AUTHENTICATION and DAEMON	MODE which follow.

   General Options
       -? | --help
	      Displays option help.

       -V | --version
	      Displays the version information for your	copy of	fetchmail.  No
	      mail fetch is performed.	Instead, for  each  server  specified,
	      all  the	option information that	would be computed if fetchmail
	      were connecting to that server is	displayed.  Any	non-printables
	      in  passwords  or	other string names are shown as	backslashed C-
	      like escape sequences.  This option is useful for	verifying that
	      your options are set the way you want them.

       -c | --check
	      Return  a	status code to indicate	whether	there is mail waiting,
	      without actually fetching	or deleting mail (see EXIT  CODES  be-
	      low).   This  option turns off daemon mode (in which it would be
	      useless).	 It doesn't play well with queries to multiple	sites,
	      and doesn't work with ETRN or ODMR.  It will return a false pos-
	      itive if you leave read but undeleted mail in your server	 mail-
	      box  and	your  fetch protocol can't tell	kept messages from new
	      ones.  This means	it will	work with IMAP,	not  work  with	 POP2,
	      and may occasionally flake out under POP3.

       -s | --silent
	      Silent  mode.   Suppresses all progress/status messages that are
	      normally echoed to standard output during	a fetch	(but does  not
	      suppress actual error messages).	The --verbose option overrides
	      this.

       -v | --verbose
	      Verbose mode.  All control messages passed between fetchmail and
	      the  mailserver are echoed to stdout.  Overrides --silent.  Dou-
	      bling this option	(-v -v)	causes extra diagnostic	information to
	      be printed.

       --nosoftbounce
	      (since v6.3.10, Keyword: set no softbounce, since	v6.3.10)
	      Hard  bounce  mode. All permanent	delivery errors	cause messages
	      to be deleted from the upstream server, see "no softbounce"  be-
	      low.

       --softbounce
	      (since v6.3.10, Keyword: set softbounce, since v6.3.10)
	      Soft  bounce  mode. All permanent	delivery errors	cause messages
	      to be left on the	upstream server	if the protocol	supports that.
	      This  option  is on by default to	match historic fetchmail docu-
	      mentation, and will be changed to	hard bounce mode in  the  next
	      fetchmail	release.

   Disposal Options
       -a | --all | (since v6.3.3) --fetchall
	      (Keyword:	fetchall, since	v3.0)
	      Retrieve	both  old (seen) and new messages from the mailserver.
	      The default is to	fetch only messages the	server has not	marked
	      seen.   Under  POP3,  this  option  also	forces the use of RETR
	      rather than TOP.	Note that POP2	retrieval  behaves  as	though
	      --all  is	always on (see RETRIEVAL FAILURE MODES below) and this
	      option does not work with	ETRN or	ODMR.  While the -a and	 --all
	      command-line and fetchall	rcfile options have been supported for
	      a	long time, the --fetchall command-line	option	was  added  in
	      v6.3.3.

       -k | --keep
	      (Keyword:	keep)
	      Keep  retrieved  messages	 on  the remote	mailserver.  Normally,
	      messages are deleted from	the folder  on	the  mailserver	 after
	      they have	been retrieved.	 Specifying the	keep option causes re-
	      trieved messages to remain in your  folder  on  the  mailserver.
	      This  option does	not work with ETRN or ODMR. If used with POP3,
	      it is recommended	to also	specify	the --uidl option or uidl key-
	      word.

       -K | --nokeep
	      (Keyword:	nokeep)
	      Delete  retrieved	messages from the remote mailserver.  This op-
	      tion forces retrieved mail to be deleted.	 It may	be  useful  if
	      you have specified a default of keep in your .fetchmailrc.  This
	      option is	forced on with ETRN and	ODMR.

       -F | --flush
	      (Keyword:	flush)
	      POP3/IMAP	only.  This is a dangerous option and can  cause  mail
	      loss  when  used improperly. It deletes old (seen) messages from
	      the mailserver before retrieving new  messages.	Warning:  This
	      can  cause  mail	loss if	you check your mail with other clients
	      than fetchmail, and cause	fetchmail to delete a message  it  had
	      never  fetched  before.  It can also cause mail loss if the mail
	      server marks the message seen after retrieval  (IMAP2  servers).
	      You  should  probably  not use this option in your configuration
	      file. If you use it with POP3, you must use the  'uidl'  option.
	      What  you	 probably  want	 is  the default setting: if you don't
	      specify '-k', then fetchmail will	automatically delete  messages
	      after successful delivery.

       --limitflush
	      POP3/IMAP	 only, since version 6.3.0.  Delete oversized messages
	      from the mailserver before retrieving  new  messages.  The  size
	      limit  should  be	 separately specified with the --limit option.
	      This option does not work	with ETRN or ODMR.

   Protocol and	Query Options
       -p <proto> | --proto <proto> | --protocol <proto>
	      (Keyword:	proto[col])
	      Specify the protocol to use when communicating with  the	remote
	      mailserver.   If	no protocol is specified, the default is AUTO.
	      proto may	be one of the following:

	      AUTO   Tries IMAP, POP3, and POP2	(skipping  any	of  these  for
		     which support has not been	compiled in).

	      POP2   Post Office Protocol 2 (legacy, to	be removed from	future
		     release)

	      POP3   Post Office Protocol 3

	      APOP   Use POP3 with old-fashioned MD5-challenge authentication.
		     Considered	not resistant to man-in-the-middle attacks.

	      RPOP   Use POP3 with RPOP	authentication.

	      KPOP   Use POP3 with Kerberos V4 authentication on port 1109.

	      SDPS   Use POP3 with Demon Internet's SDPS extensions.

	      IMAP   IMAP2bis,	IMAP4,	or  IMAP4rev1 (fetchmail automatically
		     detects their capabilities).

	      ETRN   Use the ESMTP ETRN	option.

	      ODMR   Use the the On-Demand Mail	Relay ESMTP profile.

       All these alternatives work in basically	the  same  way	(communicating
       with standard server daemons to fetch mail already delivered to a mail-
       box on the server) except ETRN and ODMR.	 The ETRN mode allows  you  to
       ask  a compliant	ESMTP server (such as BSD sendmail at release 8.8.0 or
       higher) to immediately open a sender-SMTP connection to your client ma-
       chine  and  begin forwarding any	items addressed	to your	client machine
       in the server's queue of	undelivered mail.   The	ODMR mode requires  an
       ODMR-capable  server  and  works	similarly to ETRN, except that it does
       not require the client machine to have a	static DNS.

       -U | --uidl
	      (Keyword:	uidl)
	      Force UIDL use (effective	only with  POP3).   Force  client-side
	      tracking	of  'newness'  of messages (UIDL stands	for "unique ID
	      listing" and is described	in RFC1939).  Use with 'keep' to use a
	      mailbox  as a baby news drop for a group of users. The fact that
	      seen messages are	skipped	is logged,  unless  error  logging  is
	      done  through  syslog  while  running in daemon mode.  Note that
	      fetchmail	may automatically enable this option depending on  up-
	      stream  server  capabilities.  Note also that this option	may be
	      removed and forced enabled in a future  fetchmail	 version.  See
	      also: --idfile.

       --idle (since 6.3.3)
	      (Keyword:	idle, since before 6.0.0)
	      Enable IDLE use (effective only with IMAP). Note that this works
	      with only	one account and	one folder  at	a  given  time,	 other
	      folders  or  accounts will not be	polled when idle is in effect!
	      While the	idle rcfile keyword had	 been  supported  for  a  long
	      time, the	--idle command-line option was added in	version	6.3.3.
	      IDLE use means that fetchmail tells the IMAP server to send  no-
	      tice of new messages, so they can	be retrieved sooner than would
	      be possible with regular polls.

       -P <portnumber> | --service <servicename>
	      (Keyword:	service) Since version 6.3.0.
	      The service option permits you to	specify	a service name to con-
	      nect  to.	  You  can specify a decimal port number here, if your
	      services database	lacks the required  service-port  assignments.
	      See  the	FAQ  item R12 and the --ssl documentation for details.
	      This replaces the	older --port option.

       --port <portnumber>
	      (Keyword:	port)
	      Obsolete version of --service that does not take service	names.
	      Note: this option	may be removed from a future version.

       --principal <principal>
	      (Keyword:	principal)
	      The  principal option permits you	to specify a service principal
	      for mutual authentication.  This is applicable to	POP3  or  IMAP
	      with  Kerberos 4 authentication only.  It	does not apply to Ker-
	      beros 5 or GSSAPI.  This option  may  be	removed	 in  a	future
	      fetchmail	version.

       -t <seconds> | --timeout	<seconds>
	      (Keyword:	timeout)
	      The  timeout option allows you to	set a server-nonresponse time-
	      out in seconds.  If a mailserver does not	send a	greeting  mes-
	      sage  or	respond	 to  commands for the given number of seconds,
	      fetchmail	will drop the connection to it.	 Without such a	 time-
	      out  fetchmail  might  hang  until the TCP connection times out,
	      trying to	fetch mail from	a down host, which may be  very	 long.
	      This  would  be particularly annoying for	a fetchmail running in
	      the background.  There is	a default timeout which	 fetchmail  -V
	      will  report.   If a given connection receives too many timeouts
	      in succession, fetchmail will consider it	wedged and stop	retry-
	      ing.   The  calling  user	will be	notified by email if this hap-
	      pens.

	      Beginning	with fetchmail 6.3.10, the SMTP	client uses the	recom-
	      mended  minimum  timeouts	 from  RFC-5321	 while waiting for the
	      SMTP/LMTP	server it is talking to.  You can raise	 the  timeouts
	      even  more,  but	you  cannot  shorten  them. This is to avoid a
	      painful situation	where fetchmail	has  been  configured  with  a
	      short  timeout  (a  minute  or less), ships a long message (many
	      MBytes) to the local MTA,	which then takes longer	 than  timeout
	      to  respond  "OK", which it eventually will; that	would mean the
	      mail gets	delivered properly, but	fetchmail cannot notice	it and
	      will thus	refetch	this big message over and over again.

       --plugin	<command>
	      (Keyword:	plugin)
	      The  plugin  option allows you to	use an external	program	to es-
	      tablish the TCP connection.  This	is useful if you want  to  use
	      ssh,  or	need some special firewalling setup.  The program will
	      be looked	up in $PATH and	can optionally be passed the  hostname
	      and  port	 as  arguments	using "%h" and "%p" respectively (note
	      that the interpolation logic is rather primitive,	and these  to-
	      kens must	be bounded by whitespace or beginning of string	or end
	      of string).  Fetchmail will write	to the plugin's	stdin and read
	      from the plugin's	stdout.

       --plugout <command>
	      (Keyword:	plugout)
	      Identical	 to  the plugin	option above, but this one is used for
	      the SMTP connections.

       -r <name> | --folder <name>
	      (Keyword:	folder[s])
	      Causes a specified non-default mail folder on the	mailserver (or
	      comma-separated list of folders) to be retrieved.	 The syntax of
	      the folder name is server-dependent.  This option	is not	avail-
	      able under POP3, ETRN, or	ODMR.

       --tracepolls
	      (Keyword:	tracepolls)
	      Tell  fetchmail  to  poll	trace information in the form 'polling
	      account %s' and 'folder %s' to the Received line	it  generates,
	      where  the  %s parts are replaced	by the user's remote name, the
	      poll label, and the folder (mailbox) where  available  (the  Re-
	      ceived  header  also  normally includes the server's true	name).
	      This can be used to facilitate mail filtering based on  the  ac-
	      count it is being	received from. The folder information is writ-
	      ten only since version 6.3.4.

       --ssl  (Keyword:	ssl)
	      Causes the connection to the mail	server	to  be	encrypted  via
	      SSL,  by	negotiating SSL	directly after connecting (SSL-wrapped
	      mode).  Please see the description of  --sslproto	 below!	  More
	      information  is available	in the README.SSL file that ships with
	      fetchmail.

	      Note that	even if	this option is omitted,	 fetchmail  may	 still
	      negotiate	 SSL  in-band  for  POP3  or IMAP, through the STLS or
	      STARTTLS feature.	 You can use the --sslproto option  to	modify
	      that behavior.

	      If no port is specified, the connection is attempted to the well
	      known port of the	SSL version of the  base  protocol.   This  is
	      generally	a different port than the port used by the base	proto-
	      col.  For	IMAP, this is port 143 for the clear protocol and port
	      993  for	the SSL	secured	protocol; for POP3, it is port 110 for
	      the clear	text and port 995 for the encrypted variant.

	      If your system lacks the corresponding  entries  from  /etc/ser-
	      vices,  see  the	--service  option and specify the numeric port
	      number as	given in the previous paragraph	(unless	your  ISP  had
	      directed you to different	ports, which is	uncommon however).

       --sslcert <name>
	      (Keyword:	sslcert)
	      For certificate-based client authentication.  Some SSL encrypted
	      servers require client side keys and certificates	for  authenti-
	      cation.	In  most  cases, this is optional.  This specifies the
	      location of the public key certificate to	be  presented  to  the
	      server  at  the  time the	SSL session is established.  It	is not
	      required (but may	be provided) if	the server  does  not  require
	      it.   It	may  be	the same file as the private key (combined key
	      and certificate file) but	this  is  not  recommended.  Also  see
	      --sslkey below.

	      NOTE: If you use client authentication, the user name is fetched
	      from the certificate's CommonName	and  overrides	the  name  set
	      with --user.

       --sslkey	<name>
	      (Keyword:	sslkey)
	      Specifies	 the  file  name  of  the client side private SSL key.
	      Some SSL encrypted servers require client	side keys and certifi-
	      cates  for  authentication.   In	most  cases, this is optional.
	      This specifies the location of the  private  key	used  to  sign
	      transactions  with the server at the time	the SSL	session	is es-
	      tablished.  It is	not required (but  may	be  provided)  if  the
	      server  does not require it. It may be the same file as the pub-
	      lic key (combined	key and	certificate file) but this is not rec-
	      ommended.

	      If a password is required	to unlock the key, it will be prompted
	      for at the time just prior to establishing the  session  to  the
	      server.  This can	cause some complications in daemon mode.

	      Also see --sslcert above.

       --sslproto <value>
	      (Keyword:	sslproto, NOTE:	semantic changes since v6.4.0)
	      This option has a	dual use, out of historic fetchmail behaviour.
	      It controls both the SSL/TLS protocol version and, if  --ssl  is
	      not specified, the STARTTLS behaviour (upgrading the protocol to
	      an SSL or	TLS connection in-band). Some other options  may  how-
	      ever make	TLS mandatory.

       Only  if	 this option and --ssl are both	missing	for a poll, there will
       be opportunistic	TLS for	POP3 and IMAP, where fetchmail will attempt to
       upgrade to TLSv1	or newer.

       Recognized  values  for --sslproto are given below. You should normally
       chose one of the	auto-negotiating options, i. e.	'auto' or one  of  the
       options	ending in a plus (+) character.	Note that depending on OpenSSL
       library version and configuration, some options cause  run-time	errors
       because the requested SSL or TLS	versions are not supported by the par-
       ticular installed OpenSSL library.

	      '', the empty string
		     Disable STARTTLS. If --ssl	is given for the same  server,
		     log  an  error  and pretend that 'auto' had been used in-
		     stead.

	      'auto' (default).	 Since	v6.4.0.	 Require  TLS.	Auto-negotiate
		     TLSv1  or	newer,	disable	 SSLv3	downgrade.  (fetchmail
		     6.3.26 and	older have auto-negotiated all protocols  that
		     their  OpenSSL  library  supported,  including the	broken
		     SSLv3).

	      'SSL23'
		     see 'auto'.

	      'SSL3' Require SSLv3 exactly. SSLv3 is broken, not supported  on
		     all systems, avoid	it if possible.	 This will make	fetch-
		     mail negotiate SSLv3 only,	and is the  only  way  besides
		     'SSL3+' to	have fetchmail 6.4.0 or	newer permit SSLv3.

	      'SSL3+'
		     same  as  'auto',	but  permit SSLv3 as well. This	is the
		     only way besides 'SSL3' to	have fetchmail 6.4.0 or	 newer
		     permit SSLv3.

	      'TLS1' Require  TLSv1. This does not negotiate TLSv1.1 or	newer,
		     and is discouraged. Replace by TLS1+  unless  the	latter
		     chokes your server.

	      'TLS1+'
		     Since v6.4.0. See 'auto'.

	      'TLS1.1'
		     Since v6.4.0. Require TLS v1.1 exactly.

	      'TLS1.1+'
		     Since  v6.4.0.  Require  TLS.  Auto-negotiate  TLSv1.1 or
		     newer.

	      'TLS1.2'
		     Since v6.4.0. Require TLS v1.2 exactly.

	      'TLS1.2+'
		     Since v6.4.0.  Require  TLS.  Auto-negotiate  TLSv1.2  or
		     newer.

	      'TLS1.3'
		     Since v6.4.0. Require TLS v1.3 exactly.

	      'TLS1.3+'
		     Since  v6.4.0.  Require  TLS.  Auto-negotiate  TLSv1.3 or
		     newer.

	      Unrecognized parameters
		     are treated the same as 'auto'.

	      NOTE: you	should hardly ever need	to use anything	other than  ''
	      (to force	an unencrypted connection) or 'auto' (to enforce TLS).

       --sslcertck
	      (Keyword:	sslcertck, default enabled since v6.4.0)
	      --sslcertck causes fetchmail to require that SSL/TLS be used and
	      disconnect if it can not successfully negotiate SSL or  TLS,  or
	      if  it  cannot  successfully verify and validate the certificate
	      and follow it to a trust anchor (or trusted  root	 certificate).
	      The  trust  anchors are given as a set of	local trusted certifi-
	      cates (see the sslcertfile  and  sslcertpath  options).  If  the
	      server certificate cannot	be obtained or is not signed by	one of
	      the trusted ones (directly or indirectly), fetchmail  will  dis-
	      connect, regardless of the sslfingerprint	option.

	      Note  that CRL (certificate revocation lists) are	only supported
	      in OpenSSL 0.9.7 and newer! Your system  clock  should  also  be
	      reasonably accurate when using this option.

       --nosslcertck
	      (Keyword:	no sslcertck, only in v6.4.X)
	      The  opposite  of	 --sslcertck,  this is a disouraged option. It
	      permits fetchmail	to continue connecting even if the server cer-
	      tificate	failed	the  verification checks.  Should only be used
	      together with --sslfingerprint.

       --sslcertfile <file>
	      (Keyword:	sslcertfile, since v6.3.17)
	      Sets the file fetchmail uses to look up local certificates.  The
	      default  is  empty.  This	can be given in	addition to --sslcert-
	      path below, and certificates specified in	--sslcertfile will  be
	      processed	before those in	--sslcertpath.	The option can be used
	      in addition to --sslcertpath.

	      The file is a  text  file.  It  contains	the  concatenation  of
	      trusted CA certificates in PEM format.

	      Note  that  using	 this option will suppress loading the default
	      SSL trusted CA certificates file unless you set the  environment
	      variable	FETCHMAIL_INCLUDE_DEFAULT_X509_CA_CERTS	to a non-empty
	      value.

       --sslcertpath <directory>
	      (Keyword:	sslcertpath)
	      Sets the directory fetchmail uses	to look	up local certificates.
	      The  default  is	your  OpenSSL default directory. The directory
	      must be hashed the way OpenSSL expects it	- every	time  you  add
	      or  modify  a  certificate in the	directory, you need to use the
	      c_rehash tool (which comes with OpenSSL in the tools/  subdirec-
	      tory).  Also,  after OpenSSL upgrades, you may need to run c_re-
	      hash; particularly when upgrading	from 0.9.X to 1.0.0.

	      This can be given	in addition to --sslcertfile above, which  see
	      for precedence rules.

	      Note that	using this option will suppress	adding the default SSL
	      trusted CA certificates directory	unless you set the environment
	      variable	FETCHMAIL_INCLUDE_DEFAULT_X509_CA_CERTS	to a non-empty
	      value.

       --sslcommonname <common name>
	      (Keyword:	sslcommonname; since v6.3.9)
	      Use of this option is discouraged. Before	using it, contact  the
	      administrator  of	 your upstream server and ask for a proper SSL
	      certificate to be	used. If that cannot be	attained, this	option
	      can  be used to specify the name (CommonName) that fetchmail ex-
	      pects on the server certificate.	A correctly configured	server
	      will  have  this set to the hostname by which it is reached, and
	      by default fetchmail will	expect as much.	Use this  option  when
	      the  CommonName is set to	some other value, to avoid the "Server
	      CommonName mismatch" warning, and	only if	 the  upstream	server
	      can't be made to use proper certificates.

       --sslfingerprint	<fingerprint>
	      (Keyword:	sslfingerprint)
	      Specify  the  fingerprint	 of the	server key (an MD5 hash	of the
	      key) in hexadecimal notation with	colons	separating  groups  of
	      two digits. The letter hex digits	must be	in upper case. This is
	      the format that fetchmail	uses to	report the fingerprint when an
	      SSL connection is	established. When this is specified, fetchmail
	      will compare the server key fingerprint with the given one,  and
	      the connection will fail if they do not match, regardless	of the
	      sslcertck	setting. The connection	will also  fail	 if  fetchmail
	      cannot  obtain  an SSL certificate from the server.  This	can be
	      used to prevent man-in-the-middle	attacks, but the finger	 print
	      from the server must be obtained or verified over	a secure chan-
	      nel, and certainly not over the same  Internet  connection  that
	      fetchmail	would use.

	      Using this option	will prevent printing certificate verification
	      errors as	long as	--nosslcertck is in effect.

	      To obtain	the fingerprint	of a certificate stored	 in  the  file
	      cert.pem,	try:

		   openssl x509	-in cert.pem -noout -md5 -fingerprint

	      For details, see x509(1ssl).

   Delivery Control Options
       -S <hosts> | --smtphost <hosts>
	      (Keyword:	smtp[host])
	      Specify  a  hunt	list  of hosts to forward mail to (one or more
	      hostnames, comma-separated). Hosts are tried in list order;  the
	      first  one that is up becomes the	forwarding target for the cur-
	      rent run.	 If this option	is not specified, 'localhost' is  used
	      as  the default.	Each hostname may have a port number following
	      the host name.  The port number is separated from	the host  name
	      by a slash; the default port is "smtp".  If you specify an abso-
	      lute path	name (beginning	with a /), it will be  interpreted  as
	      the name of a UNIX socket	accepting LMTP connections (such as is
	      supported	by the Cyrus IMAP daemon) Example:

		   --smtphost server1,server2/2525,server3,/var/imap/socket/lmtp

	      This option can be used with ODMR, and will make fetchmail a re-
	      lay between the ODMR server and SMTP or LMTP receiver.

	      WARNING:	if  you	use address numeric IP addresses here, be sure
	      to use --smtpaddress or --smtpname (either of which see) with  a
	      valid SMTP address literal!

       --fetchdomains <hosts>
	      (Keyword:	fetchdomains)
	      In  ETRN or ODMR mode, this option specifies the list of domains
	      the server should	ship mail for once the	connection  is	turned
	      around.	The  default is	the FQDN of the	machine	running	fetch-
	      mail.

       -D <domain> | --smtpaddress <domain>
	      (Keyword:	smtpaddress)
	      Specify the domain to be appended	to addresses in	RCPT TO	 lines
	      shipped  to  SMTP.  When	this is	not specified, the name	of the
	      SMTP server (as specified	by --smtphost) is used	for  SMTP/LMTP
	      and 'localhost' is used for UNIX socket/BSMTP.

	      NOTE:  if	 you intend to use numeric addresses, or so-called ad-
	      dress literals per the SMTP standard, write them in proper  SMTP
	      syntax,  for  instance  --smtpaddress "[192.0.2.6]" or --smtpad-
	      dress "[IPv6:2001:DB8::6]".

       --smtpname <user@domain>
	      (Keyword:	smtpname)
	      Specify the domain and user to be	put in RCPT TO	lines  shipped
	      to  SMTP.	  The  default	user is	the current local user.	Please
	      also see the  NOTE  about	 --smtpaddress	and  address  literals
	      above.

       -Z <nnn>	| --antispam <nnn[, nnn]...>
	      (Keyword:	antispam)
	      Specifies	 the list of numeric SMTP errors that are to be	inter-
	      preted as	a spam-block response from the listener.  A  value  of
	      -1  disables this	option.	 For the command-line option, the list
	      values should be comma-separated.	 Note that the antispam	values
	      only  apply  to "MAIL FROM" responses in the SMTP/LMTP dialogue,
	      but several MTAs (Postfix	in its default	configuration,	qmail)
	      defer the	anti-spam response code	until after the	RCPT TO. --an-
	      tispam does not work in these circumstances.  Also  see  --soft-
	      bounce (default) and its inverse.

       -m <command> | --mda <command>
	      (Keyword:	mda)
	      This option lets fetchmail use a Message or Local	Delivery Agent
	      (MDA or LDA) directly, rather than forward via SMTP or LMTP.

	      To avoid losing mail, use	this option only with MDAs like	 mail-
	      drop  or	MTAs  like sendmail that exit with a nonzero status on
	      disk-full	and other delivery errors; the	nonzero	 status	 tells
	      fetchmail	that delivery failed and prevents the message from be-
	      ing deleted on the server.

	      If fetchmail is running as root, it sets its user	id  while  de-
	      livering	mail  through  an  MDA	as follows:  First, the	FETCH-
	      MAILUSER,	LOGNAME, and USER environment variables	are checked in
	      this  order.  The	value of the first variable from his list that
	      is defined (even if it is	empty!)	is looked  up  in  the	system
	      user  database.  If  none	of the variables is defined, fetchmail
	      will use the real	user id	it was started with.  If  one  of  the
	      variables	 was  defined,	but the	user stated there isn't	found,
	      fetchmail	continues running as root, without checking  remaining
	      variables	 on the	list.  Practically, this means that if you run
	      fetchmail	as root	(not recommended), it is most useful to	define
	      the  FETCHMAILUSER environment variable to set the user that the
	      MDA should run as. Some MDAs (such as maildrop) are designed  to
	      be  setuid  root	and  setuid to the recipient's user id,	so you
	      don't lose functionality this way	even when running fetchmail as
	      unprivileged user.  Check	the MDA's manual for details.

	      Some  possible  MDAs  are	 "/usr/sbin/sendmail  -i  -f %F	-- %T"
	      (Note: some several older	or vendor sendmail versions mistake --
	      for  an address, rather than an indicator	to mark	the end	of the
	      option arguments), "/usr/bin/deliver" and	"/usr/bin/maildrop  -d
	      %T".   Local  delivery  addresses	 will be inserted into the MDA
	      command wherever you place a %T; the mail	message's From address
	      will be inserted where you place an %F.

	      Do  NOT  enclose the %F or %T string in single quotes!  For both
	      %T and %F, fetchmail encloses the	 addresses  in	single	quotes
	      ('),  after  removing any	single quotes they may contain,	before
	      the MDA command is passed	to the shell.

	      Do NOT use an MDA	invocation that	dispatches on the contents  of
	      To/Cc/Bcc, like "sendmail	-i -t" or "qmail-inject", it will cre-
	      ate mail loops and bring the just	wrath of many postmasters down
	      upon  your head.	This is	one of the most	frequent configuration
	      errors!

	      Also, do not try to combine multidrop mode with an MDA  such  as
	      maildrop	that can only accept one address, unless your upstream
	      stores one copy of the message per recipient and transports  the
	      envelope recipient in a header; you will lose mail.

	      The  well-known  procmail(1)  package  is	very hard to configure
	      properly,	it has a very nasty "fall through to  the  next	 rule"
	      behavior on delivery errors (even	temporary ones,	such as	out of
	      disk space if another user's  mail  daemon  copies  the  mailbox
	      around  to  purge	old messages), so your mail will end up	in the
	      wrong mailbox sooner or later. The proper	procmail configuration
	      is outside the scope of this document. Using maildrop(1) is usu-
	      ally much	easier,	and many users find the	filter syntax used  by
	      maildrop easier to understand.

	      Finally,	we  strongly  advise that you do not use qmail-inject.
	      The command line interface  is  non-standard  without  providing
	      benefits for typical use,	and fetchmail makes no attempts	to ac-
	      commodate	qmail-inject's deviations from the standard.  Some  of
	      qmail-inject's command-line and environment options are actually
	      dangerous	and can	cause broken threads,  non-detected  duplicate
	      messages and forwarding loops.

       --lmtp (Keyword:	lmtp)
	      Cause  delivery via LMTP (Local Mail Transfer Protocol).	A ser-
	      vice host	and port must be explicitly specified on each host  in
	      the  smtphost  hunt list (see above) if this option is selected;
	      the default port 25 will (in accordance with RFC	2033)  not  be
	      accepted.

       --bsmtp <filename>
	      (Keyword:	bsmtp)
	      Append  fetched  mail to a BSMTP file.  This simply contains the
	      SMTP commands that would normally	be generated by	fetchmail when
	      passing mail to an SMTP listener daemon.

	      An  argument of '-' causes the SMTP batch	to be written to stan-
	      dard output, which is of limited use: this only makes sense  for
	      debugging, because fetchmail's regular output is interspersed on
	      the same channel,	so this	isn't suitable for mail	delivery. This
	      special mode may be removed in a later release.

	      Note  that  fetchmail's  reconstruction of MAIL FROM and RCPT TO
	      lines is not guaranteed correct; the caveats discussed under THE
	      USE AND ABUSE OF MULTIDROP MAILBOXES below apply.	 This mode has
	      precedence before	--mda and SMTP/LMTP.

       --bad-header {reject|accept}
	      (Keyword:	bad-header; since v6.3.15)
	      Specify how fetchmail is supposed	to  treat  messages  with  bad
	      headers, i. e. headers with bad syntax. Traditionally, fetchmail
	      has rejected  such  messages,  but  some	distributors  modified
	      fetchmail	 to accept them. You can now configure fetchmail's be-
	      haviour per server.

   Resource Limit Control Options
       -l <maxbytes> | --limit <maxbytes>
	      (Keyword:	limit)
	      Takes a maximum octet size argument, where 0 is the default  and
	      also the special value designating "no limit".  If nonzero, mes-
	      sages larger than	this size will not be fetched and will be left
	      on  the  server  (in  foreground sessions, the progress messages
	      will note	that they are "oversized").   If  the  fetch  protocol
	      permits  (in particular, under IMAP or POP3 without the fetchall
	      option) the message will not be marked seen.

	      An explicit --limit of 0 overrides any limits set	 in  your  run
	      control  file.  This  option  is	intended  for those needing to
	      strictly control fetch time due to expensive and variable	 phone
	      rates.

	      Combined	with  --limitflush, it can be used to delete oversized
	      messages waiting on a server.  In	daemon mode, oversize  notifi-
	      cations  are  mailed to the calling user (see the	--warnings op-
	      tion). This option does not work with ETRN or ODMR.

       -w <interval> | --warnings <interval>
	      (Keyword:	warnings)
	      Takes an interval	in seconds.  When you call  fetchmail  with  a
	      'limit'  option  in  daemon  mode, this controls the interval at
	      which warnings about oversized messages are mailed to the	 call-
	      ing  user	 (or  the  user	specified by the 'postmaster' option).
	      One such notification is always mailed at	the  end  of  the  the
	      first  poll that the oversized message is	detected.  Thereafter,
	      re-notification is suppressed until after	the  warning  interval
	      elapses  (it  will  take place at	the end	of the first following
	      poll).

       -b <count> | --batchlimit <count>
	      (Keyword:	batchlimit)
	      Specify the maximum number of messages that will be  shipped  to
	      an SMTP listener before the connection is	deliberately torn down
	      and rebuilt (defaults to 0,  meaning  no	limit).	  An  explicit
	      --batchlimit  of	0 overrides any	limits set in your run control
	      file.  While sendmail(8) normally	initiates delivery of  a  mes-
	      sage  immediately	 after	receiving the message terminator, some
	      SMTP listeners are not so	prompt.	 MTAs like smail(8)  may  wait
	      till the delivery	socket is shut down to deliver.	 This may pro-
	      duce annoying delays when	fetchmail  is  processing  very	 large
	      batches.	Setting	the batch limit	to some	nonzero	size will pre-
	      vent these delays.  This option does not work with ETRN or ODMR.

       -B <number> | --fetchlimit <number>
	      (Keyword:	fetchlimit)
	      Limit the	number of messages accepted from a given server	 in  a
	      single poll.  By default there is	no limit. An explicit --fetch-
	      limit of 0 overrides any limits set in your  run	control	 file.
	      This option does not work	with ETRN or ODMR.

       --fetchsizelimit	<number>
	      (Keyword:	fetchsizelimit)
	      Limit  the  number  of  sizes  of	messages accepted from a given
	      server in	a single transaction.  This option is useful in	reduc-
	      ing  the	delay in downloading the first mail when there are too
	      many mails in the	mailbox.  By default, the limit	 is  100.   If
	      set  to  0,  sizes  of all messages are downloaded at the	start.
	      This option does not work	with ETRN or ODMR.  For	POP3, the only
	      valid non-zero value is 1.

       --fastuidl <number>
	      (Keyword:	fastuidl)
	      Do  a  binary instead of linear search for the first unseen UID.
	      Binary search avoids downloading the UIDs	 of  all  mails.  This
	      saves  time  (especially	in  daemon mode) where downloading the
	      same set of UIDs in each poll is a waste of bandwidth. The  num-
	      ber  'n' indicates how rarely a linear search should be done. In
	      daemon mode, linear search  is  used  once  followed  by	binary
	      searches	in 'n-1' polls if 'n' is greater than 1; binary	search
	      is always	used if	'n' is 1; linear search	is always used if  'n'
	      is  0.  In  non-daemon  mode, binary search is used if 'n' is 1;
	      otherwise	linear search is used. The default value of 'n'	is  4.
	      This option works	with POP3 only.

       -e <count> | --expunge <count>
	      (Keyword:	expunge)
	      Arrange  for  deletions to be made final after a given number of
	      messages.	 Under POP2 or POP3, fetchmail cannot  make  deletions
	      final  without  sending QUIT and ending the session -- with this
	      option on, fetchmail will	break a	long  mail  retrieval  session
	      into multiple sub-sessions, sending QUIT after each sub-session.
	      This is a	good defense against line drops	on POP3	servers.   Un-
	      der  IMAP,  fetchmail  normally  issues an EXPUNGE command after
	      each deletion in order to	force the deletion to be done  immedi-
	      ately.   This  is	 safest	 when your connection to the server is
	      flaky and	expensive, as it avoids	resending duplicate mail after
	      a	 line hit.  However, on	large mailboxes	the overhead of	re-in-
	      dexing after every message can slam the server pretty  hard,  so
	      if  your	connection  is reliable	it is good to do expunges less
	      frequently.  Also	note that some servers enforce a  delay	 of  a
	      few seconds after	each quit, so fetchmail	may not	be able	to get
	      back in immediately after	an expunge -- you may see "lock	 busy"
	      errors if	this happens. If you specify this option to an integer
	      N, it tells fetchmail  to	 only  issue  expunges	on  every  Nth
	      delete.  An argument of zero suppresses expunges entirely	(so no
	      expunges at all will be done until the end of run).  This	option
	      does not work with ETRN or ODMR.

   Authentication Options
       -u <name> | --user <name> | --username <name>
	      (Keyword:	user[name])
	      Specifies	 the user identification to be used when logging in to
	      the mailserver.  The appropriate	user  identification  is  both
	      server  and  user-dependent.   The default is your login name on
	      the client machine that is running fetchmail.  See USER  AUTHEN-
	      TICATION below for a complete description.

       -I <specification> | --interface	<specification>
	      (Keyword:	interface)
	      Require  that  a specific	interface device be up and have	a spe-
	      cific local or remote IPv4 (IPv6 is not supported	by this	option
	      yet) address (or range) before polling.  Frequently fetchmail is
	      used over	a transient point-to-point TCP/IP link established di-
	      rectly  to  a  mailserver	via SLIP or PPP.  That is a relatively
	      secure channel.  But when	other TCP/IP routes to the  mailserver
	      exist  (e.g.  when  the  link is connected to an alternate ISP),
	      your username and	password may be	vulnerable to snooping	(espe-
	      cially when daemon mode automatically polls for mail, shipping a
	      clear password over the  net  at	predictable  intervals).   The
	      --interface option may be	used to	prevent	this.  When the	speci-
	      fied link	is not up or is	not connected to  a  matching  IP  ad-
	      dress, polling will be skipped.  The format is:

		   interface/iii.iii.iii.iii[/mmm.mmm.mmm.mmm]

	      The  field  before  the  first slash is the interface name (i.e.
	      sl0, ppp0	etc.).	The field before the second slash is  the  ac-
	      ceptable IP address.  The	field after the	second slash is	a mask
	      which specifies a	range of IP addresses to accept.  If  no  mask
	      is  present  255.255.255.255  is	assumed	(i.e. an exact match).
	      This option is currently only supported under Linux and FreeBSD.
	      Please  see  the	monitor	section	for below for FreeBSD specific
	      information.

	      Note that	this option may	be removed  from  a  future  fetchmail
	      version.

       -M <interface> |	--monitor <interface>
	      (Keyword:	monitor)
	      Daemon  mode  can	 cause transient links which are automatically
	      taken down after a period	of inactivity (e.g. PPP	links) to  re-
	      main  up	indefinitely.	This option identifies a system	TCP/IP
	      interface	to be monitored	for activity.  After each poll	inter-
	      val, if the link is up but no other activity has occurred	on the
	      link, then the poll will be skipped.  However, when fetchmail is
	      woken  up	by a signal, the monitor check is skipped and the poll
	      goes through unconditionally.  This  option  is  currently  only
	      supported	 under	Linux and FreeBSD.  For	the monitor and	inter-
	      face options to work for	non  root  users  under	 FreeBSD,  the
	      fetchmail	 binary	 must be installed SGID	kmem.  This would be a
	      security hole, but fetchmail runs	with the effective GID set  to
	      that  of	the  kmem group	only when interface data is being col-
	      lected.

	      Note that	this option may	be removed  from  a  future  fetchmail
	      version.

       --auth <type>
	      (Keyword:	auth[enticate])
	      This  option  permits you	to specify an authentication type (see
	      USER AUTHENTICATION below	for details).  The possible values are
	      any,  password,  kerberos_v5, kerberos (or, for excruciating ex-
	      actness, kerberos_v4), gssapi, cram-md5, otp,  ntlm,  msn	 (only
	      for POP3), external (only	IMAP) and ssh.	When any (the default)
	      is specified, fetchmail tries first methods that don't require a
	      password	(EXTERNAL,  GSSAPI,  KERBEROS IV, KERBEROS 5); then it
	      looks for	methods	that mask your password	(CRAM-MD5, NTLM, X-OTP
	      -	note that MSN is only supported	for POP3, but not autoprobed);
	      and only if the server doesn't support any of those will it ship
	      your password en clair.  Other values may	be used	to force vari-
	      ous authentication methods (ssh suppresses authentication	and is
	      thus useful for IMAP PREAUTH).  (external	suppresses authentica-
	      tion and is thus useful for IMAP	EXTERNAL).   Any  value	 other
	      than password, cram-md5, ntlm, msn or otp	suppresses fetchmail's
	      normal inquiry for a password.  Specify ssh when you  are	 using
	      an  end-to-end  secure connection	such as	an ssh tunnel; specify
	      external when you	use TLS	with client authentication and specify
	      gssapi  or  kerberos_v4 if you are using a protocol variant that
	      employs GSSAPI or	K4.  Choosing KPOP protocol automatically  se-
	      lects  Kerberos  authentication.	This option does not work with
	      ETRN.  GSSAPI service names are in line with RFC-2743  and  IANA
	      registrations, see Generic Security Service Application Program
	      Interface	(GSSAPI)/Kerberos/Simple Authentication	and Security
	      Layer (SASL) Service Names <https://www.iana.org/assignments/
	      gssapi-service-names/>.

   Miscellaneous Options
       -f <pathname> | --fetchmailrc <pathname>
	      Specify a	non-default name for the  ~/.fetchmailrc  run  control
	      file.   The pathname argument must be either "-" (a single dash,
	      meaning to read the configuration	 from  standard	 input)	 or  a
	      filename.	  Unless the --version option is also on, a named file
	      argument	must  have  permissions	 no  more   open   than	  0700
	      (u=rwx,g=,o=) or else be /dev/null.

       -i <pathname> | --idfile	<pathname>
	      (Keyword:	idfile)
	      Specify  an  alternate  name for the .fetchids file used to save
	      message UIDs. NOTE: since	fetchmail 6.3.0, write access  to  the
	      directory	containing the idfile is required, as fetchmail	writes
	      a	temporary file and renames it into the place of	the  real  id-
	      file  only  if the temporary file	has been written successfully.
	      This avoids the truncation of idfiles when running out  of  disk
	      space.

       --pidfile <pathname>
	      (Keyword:	pidfile; since fetchmail v6.3.4)
	      Override the default location of the PID file. Default: see "EN-
	      VIRONMENT" below.

       -n | --norewrite
	      (Keyword:	no rewrite)
	      Normally,	fetchmail edits	RFC-822	address	headers	(To, From, Cc,
	      Bcc, and Reply-To) in fetched mail so that any mail IDs local to
	      the server are expanded to full addresses	(@ and the  mailserver
	      hostname	are  appended).	 This enables replies on the client to
	      get addressed correctly (otherwise your mailer might think  they
	      should  be  addressed  to	 local	users on the client machine!).
	      This option disables the rewrite.	 (This option is  provided  to
	      pacify  people  who  are	paranoid about having an MTA edit mail
	      headers and want to know they can	prevent	it, but	it  is	gener-
	      ally  not	a good idea to actually	turn off rewrite.)  When using
	      ETRN or ODMR, the	rewrite	option is ineffective.

       -E <line> | --envelope <line>
	      (Keyword:	envelope; Multidrop only)
	      In the configuration file, an enhanced syntax is used:
	      envelope [<count>] <line>

	      This option changes the header fetchmail assumes	will  carry  a
	      copy  of the mail's envelope address.  Normally this is 'X-Enve-
	      lope-To'.	 Other typically found headers to carry	 envelope  in-
	      formation	 are  'X-Original-To'  and 'Delivered-To'.  Now, since
	      these headers are	not standardized,  practice  varies.  See  the
	      discussion  of  multidrop	 address handling below.  As a special
	      case, 'envelope "Received"' enables  parsing  of	sendmail-style
	      Received lines.  This is the default, but	discouraged because it
	      is not fully reliable.

	      Note that	fetchmail expects the Received-line to be  in  a  spe-
	      cific  format: It	must contain "by host for address", where host
	      must match one of	the mailserver names that fetchmail recognizes
	      for the account in question.

	      The optional count argument (only	available in the configuration
	      file) determines how many	header lines of	this kind are skipped.
	      A	 count of 1 means: skip	the first, take	the second. A count of
	      2	means: skip the	first and second, take the third, and so on.

       -Q <prefix> | --qvirtual	<prefix>
	      (Keyword:	qvirtual; Multidrop only)
	      The string prefix	assigned to this option	will be	 removed  from
	      the  user	 name  found in	the header specified with the envelope
	      option (before  doing  multidrop	name  mapping  or  localdomain
	      checking,	if either is applicable). This option is useful	if you
	      are using	fetchmail to collect the mail for an entire domain and
	      your  ISP	 (or  your  mail redirection provider) is using	qmail.
	      One of the basic features	of qmail is the	Delivered-To:  message
	      header.  Whenever	qmail delivers a message to a local mailbox it
	      puts the username	and hostname of	the envelope recipient on this
	      line.   The  major reason	for this is to prevent mail loops.  To
	      set up qmail to batch mail for a disconnected site the ISP-mail-
	      host will	have normally put that site in its 'Virtualhosts' con-
	      trol file	so it will add a prefix	to all mail addresses for this
	      site.  This  results  in	mail  sent to 'username@userhost.user-
	      dom.dom.com' having a Delivered-To: line of the form:

	      Delivered-To: mbox-userstr-username@userhost.example.com

	      The ISP can make the 'mbox-userstr-' prefix anything they	choose
	      but  a  string  matching the user	host name is likely.  By using
	      the option 'envelope Delivered-To:' you can make fetchmail reli-
	      ably  identify  the original envelope recipient, but you have to
	      strip the	'mbox-userstr-'	prefix to deliver to the correct user.
	      This is what this	option is for.

       --configdump
	      Parse  the  ~/.fetchmailrc  file,	interpret any command-line op-
	      tions specified, and dump	a  configuration  report  to  standard
	      output.  The configuration report	is a data structure assignment
	      in the language Python.  This option is meant to be used with an
	      interactive ~/.fetchmailrc editor	like fetchmailconf, written in
	      Python.

       -y | --yydebug
	      Enables parser debugging,	this option is meant to	be used	by de-
	      velopers only.

   Removed Options
       -T | --netsec
	      Removed before version 6.3.0, the	required underlying inet6_apps
	      library had been discontinued and	is no longer available.

USER AUTHENTICATION AND	ENCRYPTION
       All modes except	ETRN require  authentication  of  the  client  to  the
       server.	 Normal	user authentication in fetchmail is very much like the
       authentication mechanism	of ftp(1).  The	correct	user-id	 and  password
       depend upon the underlying security system at the mailserver.

       If  the mailserver is a Unix machine on which you have an ordinary user
       account,	your regular login name	and password are used with  fetchmail.
       If  you	use  the same login name on both the server and	the client ma-
       chines, you needn't worry about specifying a user-id with the -u	option
       -- the default behavior is to use your login name on the	client machine
       as the user-id on the server machine.  If you  use  a  different	 login
       name on the server machine, specify that	login name with	the -u option.
       e.g. if your login name is 'jsmith' on a	machine	named 'mailgrunt', you
       would start fetchmail as	follows:

	      fetchmail	-u jsmith mailgrunt

       The  default behavior of	fetchmail is to	prompt you for your mailserver
       password	before the connection is established.  This is the safest  way
       to  use	fetchmail  and	ensures	that your password will	not be compro-
       mised.  You may also specify your password in your ~/.fetchmailrc file.
       This is convenient when using fetchmail in daemon mode or with scripts.

   Using netrc files
       If you do not specify a password, and fetchmail cannot extract one from
       your ~/.fetchmailrc file, it will look for a ~/.netrc file in your home
       directory before	requesting one interactively; if an entry matching the
       mailserver is found in that file, the password will be used.  Fetchmail
       first looks for a match on poll name; if	it finds none, it checks for a
       match on	via name.  See the ftp(1) man page for details of  the	syntax
       of the ~/.netrc file.  To show a	practical example, a .netrc might look
       like this:

	      machine hermes.example.org
	      login joe
	      password topsecret

       You can repeat this block with different	user information if  you  need
       to provide more than one	password.

       This feature may	allow you to avoid duplicating password	information in
       more than one file.

       On mailservers that do not provide ordinary user	accounts, your user-id
       and  password are usually assigned by the server	administrator when you
       apply for a mailbox on the server.  Contact your	 server	 administrator
       if you don't know the correct user-id and password for your mailbox ac-
       count.

POP3 VARIANTS
       Early versions of POP3 (RFC1081,	RFC1225) supported a crude form	of in-
       dependent authentication	using the .rhosts file on the mailserver side.
       Under this RPOP variant,	a fixed	per-user ID equivalent to  a  password
       was sent	in clear over a	link to	a reserved port, with the command RPOP
       rather than PASS	to alert the server that it should do  special	check-
       ing.   RPOP  is supported by fetchmail (you can specify 'protocol RPOP'
       to have the program send	'RPOP' rather than  'PASS')  but  its  use  is
       strongly	 discouraged, and support will be removed from a future	fetch-
       mail version.  This facility was	vulnerable to spoofing and  was	 with-
       drawn in	RFC1460.

       RFC1460	introduced  APOP authentication.  In this variant of POP3, you
       register	an APOP	password on your server	host  (on  some	 servers,  the
       program to do this is called popauth(8)).  You put the same password in
       your ~/.fetchmailrc file.  Each time fetchmail logs in, it sends	an MD5
       hash of your password and the server greeting time to the server, which
       can verify it by	checking its authorization database.

       Note that APOP is no longer considered  resistant  against  man-in-the-
       middle attacks.

   RETR	or TOP
       fetchmail  makes	 some  efforts to make the server believe messages had
       not been	retrieved, by using the	TOP command with  a  large  number  of
       lines  when  possible.  TOP is a	command	that retrieves the full	header
       and a fetchmail-specified amount	of body	 lines.	 It  is	 optional  and
       therefore  not implemented by all servers, and some are known to	imple-
       ment it improperly. On many servers however, the	RETR command which re-
       trieves	the  full  message  with header	and body, sets the "seen" flag
       (for instance, in a web interface), whereas the TOP command does	not do
       that.

       fetchmail  will	always	use  the  RETR	command	 if "fetchall" is set.
       fetchmail will also use the RETR	command	if "keep" is set and "uidl" is
       unset.	Finally,  fetchmail  will  use the RETR	command	on Maillennium
       POP3/PROXY servers (used	by Comcast) to avoid a deliberate  TOP	misin-
       terpretation in this server that	causes message corruption.

       In  all	other  cases, fetchmail	will use the TOP command. This implies
       that in "keep" setups, "uidl" must be set if "TOP" is desired.

       Note that this description is true for the current  version  of	fetch-
       mail,  but  the	behavior may change in future versions.	In particular,
       fetchmail may prefer the	RETR command because the  TOP  command	causes
       much grief on some servers and is only optional.

ALTERNATE AUTHENTICATION FORMS
       If  your	fetchmail was built with Kerberos support and you specify Ker-
       beros authentication (either with --auth	or the .fetchmailrc option au-
       thenticate  kerberos_v4)	 it will try to	get a Kerberos ticket from the
       mailserver at the start of each query.  Note: if	either the pollname or
       via  name  is 'hesiod', fetchmail will try to use Hesiod	to look	up the
       mailserver.

       If you use POP3 or IMAP with GSSAPI authentication, fetchmail will  ex-
       pect  the server	to have	RFC1731- or RFC1734-conforming GSSAPI capabil-
       ity, and	will use it.  Currently	this has only been  tested  over  Ker-
       beros  V,  so you're expected to	already	have a ticket-granting ticket.
       You may pass a username different from your principal  name  using  the
       standard	--user command or by the .fetchmailrc option user.

       If  your	IMAP daemon returns the	PREAUTH	response in its	greeting line,
       fetchmail will notice this and skip  the	 normal	 authentication	 step.
       This  can  be useful, e.g. if you start imapd explicitly	using ssh.  In
       this case you can declare the authentication value 'ssh'	on  that  site
       entry  to stop .fetchmail from asking you for a password	when it	starts
       up.

       If you use client authentication	with TLS1 and your IMAP	daemon returns
       the AUTH=EXTERNAL response, fetchmail will notice this and will use the
       authentication shortcut and will	not send the passphrase. In this  case
       you can declare the authentication value	'external'
	on  that site to stop fetchmail	from asking you	for a password when it
       starts up.

       If you are using	POP3, and the server issues a one-time-password	 chal-
       lenge conforming	to RFC1938, fetchmail will use your password as	a pass
       phrase to generate the required response. This avoids  sending  secrets
       over the	net unencrypted.

       Compuserve's  RPA  authentication  is  supported. If you	compile	in the
       support,	fetchmail will try to perform an RPA  pass-phrase  authentica-
       tion instead of sending over the	password en clair if it	detects	"@com-
       puserve.com" in the hostname.

       If you are using	IMAP, Microsoft's NTLM authentication (used by	Micro-
       soft  Exchange)	is supported. If you compile in	the support, fetchmail
       will try	to perform an NTLM authentication (instead of sending over the
       password	 en  clair) whenever the server	returns	AUTH=NTLM in its capa-
       bility response.	Specify	a user option value that looks like  'user@do-
       main': the part to the left of the @ will be passed as the username and
       the part	to the right as	the NTLM domain.

   Secure Socket Layers	(SSL) and Transport Layer Security (TLS)
       All retrieval protocols can use SSL or TLS wrapping for the  transport.
       Additionally,  POP3  and	 IMAP  retrival	 can also negotiate SSL/TLS by
       means of	STARTTLS (or STLS).

       Note that fetchmail currently uses the OpenSSL library,	which  is  se-
       verely underdocumented, so failures may occur just because the program-
       mers are	not aware of OpenSSL's requirement of the day.	For  instance,
       since  v6.3.16,	fetchmail calls	OpenSSL_add_all_algorithms(), which is
       necessary to support certificates using SHA256 on OpenSSL 0.9.8 -- this
       information  is deeply hidden in	the documentation and not at all obvi-
       ous.  Please do not hesitate to report subtle SSL failures.

       You can access SSL encrypted services by	specifying the options	start-
       ing  with  --ssl,  such	as --ssl, --sslproto, --sslcertck, and others.
       You can also do this  using  the	 corresponding	user  options  in  the
       .fetchmailrc  file.  Some services, such	as POP3	and IMAP, have differ-
       ent well	known ports defined for	the SSL	encrypted services.   The  en-
       crypted ports will be selected automatically when SSL is	enabled	and no
       explicit	port is	specified.   Also, the	--sslcertck  command  line  or
       sslcertck  run  control file option should be used to force strict cer-
       tificate	checking with older fetchmail versions - see below.

       If SSL is not configured, fetchmail will	usually	opportunistically  try
       to  use STARTTLS. STARTTLS can be enforced by using --sslproto auto and
       defeated	by using --sslproto ''.	 TLS connections use the same port  as
       the  unencrypted	 version of the	protocol and negotiate TLS via special
       command.	The --sslcertck	command	line or	sslcertck run control file op-
       tion should be used to force strict certificate checking	- see below.

       --sslcertck  is recommended: When connecting to an SSL or TLS encrypted
       server, the server presents a certificate to the	client for validation.
       The  certificate	 is checked to verify that the common name in the cer-
       tificate	matches	the name of the	server being contacted	and  that  the
       effective  and  expiration dates	in the certificate indicate that it is
       currently valid.	 If any	of these checks	fail,  a  warning  message  is
       printed,	but the	connection continues.  The server certificate does not
       need to be signed by any	specific Certifying Authority  and  may	 be  a
       "self-signed"  certificate.  If	the --sslcertck	command	line option or
       sslcertck run control file option is used, fetchmail will instead abort
       if  any	of  these  checks fail,	because	it must	assume that there is a
       man-in-the-middle attack	in this	scenario, hence	fetchmail must not ex-
       pose cleartext passwords. Use of	the sslcertck or --sslcertck option is
       therefore advised; it has become	the default in fetchmail 6.4.0.

       Some SSL	encrypted servers may request a	client	side  certificate.   A
       client  side  public  SSL certificate and private SSL key may be	speci-
       fied.  If requested by the server, the client certificate  is  sent  to
       the  server  for	 validation.   Some servers may	require	a valid	client
       certificate and may refuse connections if a certificate is not provided
       or  if  the  certificate	is not valid.  Some servers may	require	client
       side certificates be signed by a	recognized Certifying Authority.   The
       format  for the key files and the certificate files is that required by
       the underlying SSL libraries (OpenSSL in	the general case).

       A word of care about the	use of SSL: While above	mentioned  setup  with
       self-signed  server  certificates  retrieved over the wires can protect
       you from	a passive eavesdropper,	it doesn't help	against	an active  at-
       tacker.	It's  clearly  an  improvement	over  sending the passwords in
       clear, but you should be	aware that a man-in-the-middle attack is triv-
       ially possible (in particular with tools	such as	dsniff <https://
       monkey.org/~dugsong/dsniff/>, ).	 Use of	 strict	 certificate  checking
       with a certification authority recognized by server and client, or per-
       haps of an SSH tunnel (see below	for some examples)  is	preferable  if
       you care	seriously about	the security of	your mailbox and passwords.

   ESMTP AUTH
       fetchmail  also	supports  authentication  to  the  ESMTP server	on the
       client side according to	RFC 2554.  You	can  specify  a	 name/password
       pair  to	be used	with the keywords 'esmtpname' and 'esmtppassword'; the
       former defaults to the username of the calling user.

DAEMON MODE
   Introducing the daemon mode
       In daemon mode, fetchmail puts itself into the background and runs for-
       ever,  querying	each  specified	 host  and  then  sleeping for a given
       polling interval.

   Starting the	daemon mode
       There are several ways to make fetchmail	work in	daemon	mode.  On  the
       command	line,  --daemon	<interval> or -d <interval> option runs	fetch-
       mail in daemon mode.  You must specify a	numeric	argument  which	 is  a
       polling interval	(time to wait after completing a whole poll cycle with
       the last	server and before starting the next poll cycle with the	 first
       server) in seconds.

       Example:	simply invoking

	      fetchmail	-d 900

       will,  therefore,  poll	all the	hosts described	in your	~/.fetchmailrc
       file (except those explicitly excluded with the 'skip' verb) a bit less
       often  than  once every 15 minutes (exactly: 15 minutes + time that the
       poll takes).

       It is also possible to set a polling interval  in  your	~/.fetchmailrc
       file  by	saying 'set daemon <interval>',	where <interval> is an integer
       number of seconds.  If you do this, fetchmail will always start in dae-
       mon mode	unless you override it with the	command-line option --daemon 0
       or -d0.

       Only one	daemon process is permitted per	user; in daemon	 mode,	fetch-
       mail  sets  up a	per-user lockfile to guarantee this.  (You can however
       cheat and set the FETCHMAILHOME environment variable to	overcome  this
       setting,	 but  in that case, it is your responsibility to make sure you
       aren't polling the same server with two processes at the	same time.)

   Awakening the background daemon
       Normally, calling fetchmail with	a daemon in  the  background  sends  a
       wake-up	signal	to the daemon and quits	without	output.	The background
       daemon then starts its next poll	cycle immediately.  The	 wake-up  sig-
       nal, SIGUSR1, can also be sent manually.	The wake-up action also	clears
       any 'wedged' flags indicating  that  connections	 have  wedged  due  to
       failed authentication or	multiple timeouts.

   Terminating the background daemon
       The  option  -q or --quit will kill a running daemon process instead of
       waking it up (if	there is no such process, fetchmail will notify	 you).
       If  the	--quit option appears last on the command line,	fetchmail will
       kill the	running	daemon process and  then  quit.	 Otherwise,  fetchmail
       will first kill a running daemon	process	and then continue running with
       the other options.

   Useful options for daemon mode
       The -L <filename> or --logfile <filename> option	(keyword: set logfile)
       is  only	 effective when	fetchmail is detached and in daemon mode. Note
       that the	logfile	must exist before fetchmail is run, you	 can  use  the
       touch(1)	command	with the filename as its sole argument to create it.
       This  option  allows  you  to redirect status messages into a specified
       logfile (follow the option with the  logfile  name).   The  logfile  is
       opened  for  append, so previous	messages aren't	deleted.  This is pri-
       marily useful for debugging configurations. Note	 that  fetchmail  does
       not  detect  if the logfile is rotated, the logfile is only opened once
       when fetchmail starts. You need to restart fetchmail after rotating the
       logfile and before compressing it (if applicable).

       The --syslog option (keyword: set syslog) allows	you to redirect	status
       and error messages emitted to the syslog(3) system daemon if available.
       Messages	are logged with	an id of fetchmail, the	facility LOG_MAIL, and
       priorities LOG_ERR, LOG_ALERT or	LOG_INFO.  This	option is intended for
       logging status and error	messages which indicate	the status of the dae-
       mon and the results while fetching mail from the	server(s).  Error mes-
       sages  for  command  line options and parsing the .fetchmailrc file are
       still written to	stderr,	or to the specified log	file.  The  --nosyslog
       option  turns  off  use	of  syslog(3),	assuming it's turned on	in the
       ~/.fetchmailrc file.  This option is overridden,	in certain situations,
       by --logfile (which see).

       The  -N or --nodetach option suppresses backgrounding and detachment of
       the daemon process from its control terminal.  This is useful  for  de-
       bugging	or  when  fetchmail  runs as the child of a supervisor process
       such as init(8) or Gerrit Pape's	runit(8).  Note	that this also	causes
       the logfile option to be	ignored.

       Note  that  while  running  in  daemon  mode polling a POP2 or IMAP2bis
       server, transient errors	(such as DNS failures or sendmail delivery re-
       fusals)	may  force the fetchall	option on for the duration of the next
       polling cycle.  This is a robustness feature.  It means that if a  mes-
       sage is fetched (and thus marked	seen by	the mailserver)	but not	deliv-
       ered locally due	to some	transient error, it will be re-fetched	during
       the  next  poll	cycle.	 (The IMAP logic doesn't delete	messages until
       they're delivered, so this problem does not arise.)

       If you touch or change the ~/.fetchmailrc file while fetchmail is  run-
       ning in daemon mode, this will be detected at the beginning of the next
       poll cycle.  When  a  changed  ~/.fetchmailrc  is  detected,  fetchmail
       rereads	it and restarts	from scratch (using exec(2); no	state informa-
       tion is retained	in the new instance).  Note that if fetchmail needs to
       query  for  passwords,  of  that	if you break the ~/.fetchmailrc	file's
       syntax, the new instance	 will  softly  and  silently  vanish  away  on
       startup.

ADMINISTRATIVE OPTIONS
       The  --postmaster <name>	option (keyword: set postmaster) specifies the
       last-resort username to which multidrop mail is to be forwarded	if  no
       matching	 local	recipient can be found.	It is also used	as destination
       of undeliverable	mail if	the 'bouncemail' global	option is off and  ad-
       ditionally  for	spam-blocked mail if the 'bouncemail' global option is
       off and the 'spambounce'	global option is on. This option  defaults  to
       the user	who invoked fetchmail.	If the invoking	user is	root, then the
       default of this option is the user 'postmaster'.	 Setting postmaster to
       the  empty string causes	such mail as described above to	be discarded -
       this however is usually a bad idea.  See	also the  description  of  the
       'FETCHMAILUSER' environment variable in the ENVIRONMENT section below.

       The  --nobounce	behaves	 like  the  "set no bouncemail"	global option,
       which see.

       The --invisible option (keyword:	set invisible) tries to	make fetchmail
       invisible.   Normally, fetchmail	behaves	like any other MTA would -- it
       generates a Received header into	each message describing	its  place  in
       the  chain  of  transmission, and tells the MTA it forwards to that the
       mail came from the machine fetchmail itself is running on.  If the  in-
       visible	option	is on, the Received header is suppressed and fetchmail
       tries to	spoof the MTA it forwards to into thinking  it	came  directly
       from the	mailserver host.

       The  --showdots option (keyword:	set showdots) forces fetchmail to show
       progress	dots even if the output	goes to	a file or fetchmail is not  in
       verbose	mode.	Fetchmail shows	the dots by default when run in	--ver-
       bose mode and output  goes  to  console.	 This  option  is  ignored  in
       --silent	mode.

       By specifying the --tracepolls option, you can ask fetchmail to add in-
       formation to the	Received header	on the form "polling  {label}  account
       {user}",	where {label} is the account label (from the specified rcfile,
       normally	~/.fetchmailrc)	and {user} is the username which  is  used  to
       log  on	to  the	mail server. This header can be	used to	make filtering
       email where no useful header information	is available and you want mail
       from  different	accounts  sorted into different	mailboxes (this	could,
       for example, occur if you have an account on the	same server running  a
       mailing	list,  and are subscribed to the list using that account). The
       default is not adding any such header.  In .fetchmailrc,	this is	called
       'tracepolls'.

RETRIEVAL FAILURE MODES
       The protocols fetchmail uses to talk to mailservers are next to bullet-
       proof.  In normal operation forwarding to port 25, no message  is  ever
       deleted	(or  even marked for deletion) on the host until the SMTP lis-
       tener on	the client side	has acknowledged to fetchmail that the message
       has been	either accepted	for delivery or	rejected due to	a spam block.

       When forwarding to an MDA, however, there is more possibility of	error.
       Some MDAs are 'safe' and	reliably return	a nonzero status on any	deliv-
       ery  error, even	one due	to temporary resource limits.  The maildrop(1)
       program is like this; so	are most programs designed as  mail  transport
       agents,	such as	sendmail(1), including the sendmail wrapper of Postfix
       and exim(1).  These programs give back a	reliable positive acknowledge-
       ment  and  can  be  used	with the mda option with no risk of mail loss.
       Unsafe MDAs, though, may	return 0 even on delivery  failure.   If  this
       happens,	you will lose mail.

       The normal mode of fetchmail is to try to download only 'new' messages,
       leaving untouched (and undeleted) messages you have  already  read  di-
       rectly  on  the	server	(or fetched with a previous fetchmail --keep).
       But you may find	that messages you've already read on  the  server  are
       being  fetched  (and deleted) even when you don't specify --all.	 There
       are several reasons this	can happen.

       One could be that you're	using POP2.  The  POP2	protocol  includes  no
       representation  of  'new' or 'old' state	in messages, so	fetchmail must
       treat all messages as new all the time.	But POP2 is obsolete, so  this
       is unlikely.

       A  potential  POP3 problem might	be servers that	insert messages	in the
       middle of mailboxes (some VMS implementations of	mail are rumored to do
       this).	The  fetchmail	code assumes that new messages are appended to
       the end of the mailbox; when this is not	true it	 may  treat  some  old
       messages	 as  new and vice versa.  Using	UIDL whilst setting fastuidl 0
       might fix this, otherwise, consider switching to	IMAP.

       Yet another POP3	problem	is that	if they	can't make  tempfiles  in  the
       user's home directory, some POP3	servers	will hand back an undocumented
       response	that causes fetchmail to spuriously report "No mail".

       The IMAP	code uses the presence or absence of the server	flag \Seen  to
       decide  whether or not a	message	is new.	 This isn't the	right thing to
       do, fetchmail should check the UIDVALIDITY and use UID, but it  doesn't
       do  that	 yet.  Under Unix, it counts on	your IMAP server to notice the
       BSD-style Status	flags set by mail user agents and set the  \Seen  flag
       from  them when appropriate.  All Unix IMAP servers we know of do this,
       though it's not specified by the	IMAP RFCs.  If you ever	 trip  over  a
       server that doesn't, the	symptom	will be	that messages you have already
       read on your host will look new to  the	server.	  In  this  (unlikely)
       case,  only messages you	fetched	with fetchmail --keep will be both un-
       deleted and marked old.

       In ETRN and ODMR	modes, fetchmail does not actually retrieve  messages;
       instead,	 it  asks the server's SMTP listener to	start a	queue flush to
       the client via SMTP.  Therefore it sends	only undelivered messages.

SPAM FILTERING
       Many SMTP listeners allow administrators	to set up 'spam	filters'  that
       block  unsolicited  email  from specified domains.  A MAIL FROM or DATA
       line that triggers this feature will elicit an SMTP response which (un-
       fortunately) varies according to	the listener.

       Newer versions of sendmail return an error code of 571.

       According  to RFC2821, the correct thing	to return in this situation is
       550 "Requested action not taken:	mailbox	unavailable" (the  draft  adds
       "[E.g.,	mailbox	 not  found, no	access,	or command rejected for	policy
       reasons].").

       Older versions of the exim MTA return 501 "Syntax error	in  parameters
       or arguments".

       The postfix MTA runs 554	as an antispam response.

       Zmailer	may  reject  code with a 500 response (followed	by an enhanced
       status code that	contains more information).

       Return codes which fetchmail treats as antispam responses and  discards
       the  message can	be set with the	'antispam' option.  This is one	of the
       only three circumstance under which fetchmail ever discards  mail  (the
       others  are the 552 and 553 errors described below, and the suppression
       of multidropped messages	with a message-ID already seen).

       If fetchmail is fetching	from an	IMAP  server,  the  antispam  response
       will be detected	and the	message	rejected immediately after the headers
       have been fetched, without reading the message body.  Thus,  you	 won't
       pay for downloading spam	message	bodies.

       By default, the list of antispam	responses is empty.

       If  the spambounce global option	is on, mail that is spam-blocked trig-
       gers an RFC1892/RFC1894 bounce message informing	the originator that we
       do not accept mail from it. See also BUGS.

SMTP/ESMTP ERROR HANDLING
       Besides	the spam-blocking described above, fetchmail takes special ac-
       tions --	that may be modified by	the --softbounce option	-- on the fol-
       lowing SMTP/ESMTP error response	codes

       452 (insufficient system	storage)
	    Leave the message in the server mailbox for	later retrieval.

       552 (message exceeds fixed maximum message size)
	    Delete the message from the	server.	 Send bounce-mail to the orig-
	    inator.

       553 (invalid sending domain)
	    Delete the message from  the  server.   Don't  even	 try  to  send
	    bounce-mail	to the originator.

       Other  errors  greater  or equal	to 500 trigger bounce mail back	to the
       originator, unless suppressed by	--softbounce. See also BUGS.

THE RUN	CONTROL	FILE
       The preferred way to set	up fetchmail is	to write a  .fetchmailrc  file
       in  your	 home directory	(you may do this directly, with	a text editor,
       or indirectly via fetchmailconf).  When there is	a conflict between the
       command-line arguments and the arguments	in this	file, the command-line
       arguments take precedence.

       To protect the security of your passwords, your ~/.fetchmailrc may  not
       normally	 have more than	0700 (u=rwx,g=,o=) permissions;	fetchmail will
       complain	and exit otherwise (this check is suppressed when --version is
       on).

       You may read the	.fetchmailrc file as a list of commands	to be executed
       when fetchmail is called	with no	arguments.

   Run Control Syntax
       Comments	begin with a '#' and extend through the	end of the line.  Oth-
       erwise the file consists	of a series of server entries or global	option
       statements in a free-format, token-oriented syntax.

       There are four kinds of tokens: grammar keywords, numbers (i.e. decimal
       digit  sequences),  unquoted  strings,  and  quoted  strings.  A	quoted
       string is bounded by double quotes  and	may  contain  whitespace  (and
       quoted  digits are treated as a string).	 Note that quoted strings will
       also contain line feed characters if they run across two	or more	lines,
       unless  you  use	 a  backslash  to join lines (see below).  An unquoted
       string is any  whitespace-delimited  token  that	 is  neither  numeric,
       string  quoted  nor  contains  the special characters ',', ';', ':', or
       '='.

       Any amount of whitespace	separates tokens in  server  entries,  but  is
       otherwise  ignored.  You	may use	backslash escape sequences (\n for LF,
       \t for HT, \b for BS, \r	for CR,	\nnn for  decimal  (where  nnn	cannot
       start with a 0),	\0ooo for octal, and \xhh for hex) to embed non-print-
       able characters or string delimiters in strings.	 In quoted strings,  a
       backslash at the	very end of a line will	cause the backslash itself and
       the line	feed (LF or NL,	new line) character to be ignored, so that you
       can  wrap long strings. Without the backslash at	the line end, the line
       feed character would become part	of the string.

       Warning:	while these resemble C-style escape sequences,	they  are  not
       the  same.  fetchmail only supports these eight styles. C supports more
       escape sequences	that consist of	backslash (\) and a single  character,
       but  does  not support decimal codes and	does not require the leading 0
       in octal	notation.  Example: fetchmail interprets \233 the same as \xE9
       (Latin  small letter e with acute), where C would interpret \233	as oc-
       tal 0233	= \x9B (CSI, control sequence introducer).

       Each server entry consists of one of the	 keywords  'poll'  or  'skip',
       followed	 by a server name, followed by server options, followed	by any
       number of user (or username) descriptions, followed  by	user  options.
       Note:  the  most	 common	 cause	of syntax errors is mixing up user and
       server options or putting user options before the user descriptions.

       For backward compatibility, the word 'server' is	a synonym for 'poll'.

       You can use the noise keywords 'and', 'with', 'has', 'wants', and  'op-
       tions'  anywhere	 in an entry to	make it	resemble English.  They're ig-
       nored, but but can make entries much easier to read at a	 glance.   The
       punctuation characters ':', ';' and ',' are also	ignored.

   Poll	vs. Skip
       The  'poll' verb	tells fetchmail	to query this host when	it is run with
       no arguments.  The 'skip' verb tells fetchmail not to  poll  this  host
       unless  it  is  explicitly named	on the command line.  (The 'skip' verb
       allows you to experiment	with test entries safely,  or  easily  disable
       entries for hosts that are temporarily down.)

   Keyword/Option Summary
       Here are	the legal options.  Keyword suffixes enclosed in square	brack-
       ets are optional.  Those	corresponding to  short	 command-line  options
       are  followed  by  '-' and the appropriate option letter.  If option is
       only relevant to	a single mode of operation, it is noted	as 's' or  'm'
       for singledrop- or multidrop-mode, respectively.

       Here are	the legal global options:

       Keyword		   Opt	 Mode	Function
       --------------------------------------------------------------------
       set daemon	   -d		Set  a background poll interval	in
					seconds.
       set postmaster			Give the name of  the  last-resort
					mail recipient (default: user run-
					ning  fetchmail,  "postmaster"	if
					run by the root	user)
       set    bouncemail		Direct	error  mail  to	the sender
					(default)
       set no bouncemail		Direct error  mail  to	the  local
					postmaster  (as	 per the 'postmas-
					ter' global option above).
       set no spambounce		Do not	bounce	spam-blocked  mail
					(default).
       set    spambounce		Bounce	blocked	 spam-blocked mail
					(as per	the  'antispam'	 user  op-
					tion)  back  to	the destination	as
					indicated  by	the   'bouncemail'
					global	option.	  Warning:  Do not
					use this to bounce  spam  back	to
					the  sender  -	most  spam is sent
					with false sender address and thus
					this  option  hurts  innocent  by-
					standers.
       set no softbounce		Delete	permanently  undeliverable
					mail.  It  is  recommended  to use
					this option if	the  configuration
					has been thoroughly tested.
       set    softbounce		Keep   permanently   undeliverable
					mail as	though a  temporary  error
					had occurred (default).
       set logfile	   -L		Name of	a file to append error and
					status messages	to.   Only  effec-
					tive  in daemon	mode and if fetch-
					mail  detaches.	   If	effective,
					overrides set syslog.
       set pidfile	   -p		Name of	the PID	file.

       set idfile	   -i		Name  of  the  file  to	 store UID
					lists in.
       set    syslog			Do  error  logging  through   sys-
					log(3).	 May  be overridden by set
					logfile.
       set no syslog			Turn  off  error  logging  through
					syslog(3). (default)
       set properties			String	value  that  is	ignored	by
					fetchmail (may be used	by  exten-
					sion scripts).

       Here are	the legal server options:

       Keyword		Opt   Mode   Function
       -----------------------------------------------------------------
       via			     Specify  DNS  name	 of mailserver,
				     overriding	poll name
       proto[col]	-p	     Specify  protocol	(case  insensi-
				     tive):  POP2,  POP3,  IMAP,  APOP,
				     KPOP
       local[domains]	      m	     Specify domain(s) to  be  regarded
				     as	local
       port			     Specify TCP/IP service port (obso-
				     lete, use 'service' instead).
       service		-P	     Specify service  name  (a	numeric
				     value  is also allowed and	consid-
				     ered a TCP/IP port	number).
       auth[enticate]		     Set authentication	 type  (default
				     'any')
       timeout		-t	     Server  inactivity	timeout	in sec-
				     onds (default 300)
       envelope		-E    m	     Specify  envelope-address	 header
				     name
       no envelope	      m	     Disable  looking  for envelope ad-
				     dress
       qvirtual		-Q    m	     Qmail virtual domain prefix to re-
				     move from user name
       aka		      m	     Specify  alternate	 DNS  names  of
				     mailserver
       interface	-I	     specify IP	interface(s) that  must
				     be	 up  for  server  poll	to take
				     place
       monitor		-M	     Specify IP	address	to monitor  for
				     activity
       plugin			     Specify  command  through which to
				     make server connections.
       plugout			     Specify command through  which  to
				     make listener connections.
       dns		      m	     Enable  DNS  lookup  for multidrop
				     (default)
       no dns		      m	     Disable DNS lookup	for multidrop
       checkalias	      m	     Do	comparison by  IP  address  for
				     multidrop
       no checkalias	      m	     Do	 comparison  by	 name  for mul-
				     tidrop (default)
       uidl		-U	     Force  POP3  to  use   client-side
				     UIDLs (recommended)
       no uidl			     Turn  off	POP3 use of client-side
				     UIDLs (default)
       interval			     Only check	this site every	N  poll
				     cycles; N is a numeric argument.
       tracepolls		     Add  poll	tracing	 information to
				     the Received header
       principal		     Set Kerberos principal (only  use-
				     ful with IMAP and kerberos)
       esmtpname		     Set  name	for RFC2554 authentica-
				     tion to the ESMTP server.
       esmtppassword		     Set password for RFC2554 authenti-
				     cation to the ESMTP server.
       bad-header		     How  to  treat messages with a bad
				     header. Can be reject (default) or
				     accept.

       Here are	the legal user descriptions and	options:

       Keyword		  Opt	    Mode   Function
       -----------------------------------------------------------------------
       user[name]	  -u		   This	 is  the user description and
					   must	come first after  server  de-
					   scription   and   after   possible
					   server options,  and	 before	 user
					   options.

					   It sets the remote user name	if by
					   itself or followed by 'there',  or
					   the local user name if followed by
					   'here'.
       is				   Connect  local  and	remote	 user
					   names
       to				   Connect   local  and	 remote	 user
					   names
       pass[word]			   Specify remote account password
       ssl				   Connect to server over the  speci-
					   fied	 base  protocol	using SSL en-
					   cryption
       sslcert				   Specify file	for client side	 pub-
					   lic SSL certificate
       sslcertck			   Enable strict certificate checking
					   and abort connection	 on  failure.
					   Default   only   since   fetchmail
					   v6.4.0.
       no sslcertck			   Disable strict certificate  check-
					   ing and permit connections to con-
					   tinue on failed verification. Dis-
					   couraged.  Should only be used to-
					   gether with sslfingerprint.
       sslcertfile			   Specify file	with trusted CA	 cer-
					   tificates
       sslcertpath			   Specify c_rehash-ed directory with
					   trusted CA certificates.
       sslfingerprint	  <HASH>	   Specify the expected	 server	 cer-
					   tificate  finger print from an MD5
					   hash.  Fetchmail  will  disconnect
					   and	log  an	 error if it does not
					   match.
       sslkey				   Specify file	for client side	 pri-
					   vate	SSL key
       sslproto				   Force ssl protocol for connection
       folder		  -r		   Specify remote folder to query
       smtphost		  -S		   Specify smtp	host(s)	to forward to
       fetchdomains		    m	   Specify  domains  for  which	 mail
					   should be fetched
       smtpaddress	  -D		   Specify the domain to  be  put  in
					   RCPT	TO lines
       smtpname				   Specify  the	user and domain	to be
					   put in RCPT TO lines
       antispam		  -Z		   Specify what	SMTP returns are  in-
					   terpreted as	spam-policy blocks
       mda		  -m		   Specify MDA for local delivery
       bsmtp				   Specify BSMTP batch file to append
					   to
       preconnect			   Command to be executed before each
					   connection
       postconnect			   Command  to be executed after each
					   connection
       keep		  -k		   Don't delete	 seen  messages	 from
					   server  (for	 POP3, uidl is recom-
					   mended)
       flush		  -F		   Flush  all  seen  messages  before
					   querying (DANGEROUS)
       limitflush			   Flush  all  oversized messages be-
					   fore	querying
       fetchall		  -a		   Fetch all messages whether seen or
					   not
       rewrite				   Rewrite  destination	addresses for
					   reply (default)

       stripcr				   Strip carriage returns  from	 ends
					   of lines
       forcecr				   Force  carriage returns at ends of
					   lines
       pass8bits			   Force BODY=8BITMIME to ESMTP	 lis-
					   tener
       dropstatus			   Strip  Status and X-Mozilla-Status
					   lines out of	incoming mail
       dropdelivered			   Strip Delivered-To  lines  out  of
					   incoming mail
       mimedecode			   Convert  quoted-printable to	8-bit
					   in MIME messages
       idle				   Idle	waiting	for new	messages  af-
					   ter each poll (IMAP only)
       no keep		  -K		   Delete  seen	 messages from server
					   (default)
       no flush				   Don't flush all seen	messages  be-
					   fore	querying (default)
       no fetchall			   Retrieve  only  new	messages (de-
					   fault)
       no rewrite			   Don't rewrite headers
       no stripcr			   Don't strip carriage	returns	 (de-
					   fault)
       no forcecr			   Don't  force	 carriage  returns at
					   EOL (default)
       no pass8bits			   Don't force BODY=8BITMIME to	ESMTP
					   listener (default)
       no dropstatus			   Don't  drop	Status	headers	 (de-
					   fault)
       no dropdelivered			   Don't  drop	Delivered-To  headers
					   (default)
       no mimedecode			   Don't  convert quoted-printable to
					   8-bit in MIME messages (default)
       no idle				   Don't idle waiting  for  new	 mes-
					   sages after each poll (IMAP only)
       limit		  -l		   Set message size limit
       warnings		  -w		   Set message size warning interval
       batchlimit	  -b		   Max	# messages to forward in sin-
					   gle connect
       fetchlimit	  -B		   Max # messages to fetch in  single
					   connect
       fetchsizelimit			   Max	#  message  sizes to fetch in
					   single transaction
       fastuidl				   Use binary search for first unseen
					   message (POP3 only)
       expunge		  -e		   Perform  an	expunge	 on every #th
					   message (IMAP and POP3 only)
       properties			   String value	is ignored by  fetch-
					   mail	 (may  be  used	 by extension
					   scripts)

       All user	options	must begin with	a user description (user  or  username
       option) and follow all server descriptions and options.

       In  the	.fetchmailrc  file, the	'envelope' string argument may be pre-
       ceded by	a whitespace-separated number.	This number, if	specified,  is
       the  number of such headers to skip over	(that is, an argument of 1 se-
       lects the second	header of the given type).  This  is  sometime	useful
       for  ignoring bogus envelope headers created by an ISP's	local delivery
       agent or	internal forwards (through mail	inspection  systems,  for  in-
       stance).

   Keywords Not	Corresponding To Option	Switches
       The  'folder' and 'smtphost' options (unlike their command-line equiva-
       lents) can take a space-	or comma-separated  list  of  names  following
       them.

       All  options  correspond	 to the	obvious	command-line arguments,	except
       the following: 'via', 'interval', 'aka',	'is',  'to',  'dns'/'no	 dns',
       'checkalias'/'no	 checkalias', 'password', 'preconnect',	'postconnect',
       'localdomains',	 'stripcr'/'no	 stripcr',   'forcecr'/'no   forcecr',
       'pass8bits'/'no	 pass8bits'  'dropstatus/no  dropstatus',  'dropdeliv-
       ered/no dropdelivered', 'mimedecode/no mimedecode', 'no idle', and  'no
       envelope'.

       The 'via' option	is for if you want to have more	than one configuration
       pointing	at the same site.  If it is present, the string	argument  will
       be  taken as the	actual DNS name	of the mailserver host to query.  This
       will override the argument of poll, which can then simply be a distinct
       label  for  the	configuration (e.g. what you would give	on the command
       line to explicitly query	this host).

       The 'interval' option (which takes a numeric argument)  allows  you  to
       poll a server less frequently than the basic poll interval.  If you say
       'interval N' the	server this option is attached to will only be queried
       every N poll intervals.

   Singledrop vs. Multidrop options
       Please  ensure  you  read  the section titled THE USE AND ABUSE OF MUL-
       TIDROP MAILBOXES	if you intend to use multidrop mode.

       The 'is'	or  'to'  keywords  associate  the  following  local  (client)
       name(s)	(or  server-name  to client-name mappings separated by =) with
       the mailserver user name	in the entry.  If an is/to list	has '*'	as its
       last  name, unrecognized	names are simply passed	through. Note that un-
       til fetchmail version 6.3.4 inclusively,	these lists could only contain
       local parts of user names (fetchmail would only look at the part	before
       the @ sign). fetchmail versions 6.3.5 and newer support full  addresses
       on  the left hand side of these mappings, and they take precedence over
       any 'localdomains', 'aka', 'via'	or similar mappings.

       A single	local name can be used to support redirecting your  mail  when
       your  username on the client machine is different from your name	on the
       mailserver.  When there is only a single	local name, mail is  forwarded
       to  that	 local	username regardless of the message's Received, To, Cc,
       and Bcc headers.	 In this case, fetchmail never does DNS	lookups.

       When there is more than one local name  (or  name  mapping),  fetchmail
       looks  at  the envelope header, if configured, and otherwise at the Re-
       ceived, To, Cc, and Bcc headers of retrieved mail (this	is  'multidrop
       mode').	 It  looks  for	 addresses with	hostname parts that match your
       poll name or your 'via',	'aka' or 'localdomains'	options,  and  usually
       also  for  hostname  parts  which  DNS  tells  it  are  aliases	of the
       mailserver.  See	the discussion of 'dns', 'checkalias', 'localdomains',
       and 'aka' for details on	how matching addresses are handled.

       If  fetchmail  cannot match any mailserver usernames or localdomain ad-
       dresses,	the mail will be bounced.  Normally it will be bounced to  the
       sender,	but if the 'bouncemail'	global option is off, the mail will go
       to the local postmaster instead.	 (see the 'postmaster' global option).
       See also	BUGS.

       The  'dns'  option  (normally  on) controls the way addresses from mul-
       tidrop mailboxes	are checked.  On, it enables logic to check each  host
       address	that  does not match an	'aka' or 'localdomains'	declaration by
       looking it up with DNS.	When a mailserver username is  recognized  at-
       tached  to  a matching hostname part, its local mapping is added	to the
       list of local recipients.

       The 'checkalias'	option (normally off) extends the lookups performed by
       the  'dns'  keyword in multidrop	mode, providing	a way to cope with re-
       mote MTAs that identify themselves using	their  canonical  name,	 while
       they're polled using an alias.  When such a server is polled, checks to
       extract the envelope address fail, and fetchmail	 reverts  to  delivery
       using  the  To/Cc/Bcc  headers  (See  below  'Header  vs.  Envelope ad-
       dresses').  Specifying this option instructs fetchmail to retrieve  all
       the  IP	addresses associated with both the poll	name and the name used
       by the remote MTA and to	do a comparison	of  the	 IP  addresses.	  This
       comes in	handy in situations where the remote server undergoes frequent
       canonical name changes, that would otherwise require  modifications  to
       the rcfile.  'checkalias' has no	effect if 'no dns' is specified	in the
       rcfile.

       The 'aka' option	is for use with	multidrop mailboxes.  It allows	you to
       pre-declare  a  list of DNS aliases for a server.  This is an optimiza-
       tion hack that allows you to trade space	for  speed.   When  fetchmail,
       while  processing  a multidrop mailbox, grovels through message headers
       looking for names of the	mailserver, pre-declaring common ones can save
       it  from	 having	 to do DNS lookups.  Note: the names you give as argu-
       ments to	'aka' are matched as suffixes -- if you	specify	(say) 'aka ne-
       taxs.com',  this	 will  match  not  just	a hostname netaxs.com, but any
       hostname	that ends with '.netaxs.com'; such  as	(say)  pop3.netaxs.com
       and mail.netaxs.com.

       The 'localdomains' option allows	you to declare a list of domains which
       fetchmail should	consider local.	 When  fetchmail  is  parsing  address
       lines in	multidrop modes, and a trailing	segment	of a host name matches
       a declared local	domain,	that address is	passed through to the listener
       or MDA unaltered	(local-name mappings are not applied).

       If you are using	'localdomains',	you may	also need to specify 'no enve-
       lope', which disables fetchmail's normal	attempt	to deduce an  envelope
       address	from  the  Received  line  or X-Envelope-To header or whatever
       header has been previously set by 'envelope'.  If you set 'no envelope'
       in the defaults entry it	is possible to undo that in individual entries
       by using	'envelope <string>'.  As a special case, 'envelope "Received"'
       restores	the default parsing of Received	lines.

       The  password  option requires a	string argument, which is the password
       to be used with the entry's server.

       The 'preconnect'	keyword	allows you to specify a	shell  command	to  be
       executed	 just before each time fetchmail establishes a mailserver con-
       nection.	 This may be useful if you are attempting to set up secure POP
       connections  with  the aid of ssh(1).  If the command returns a nonzero
       status, the poll	of that	mailserver will	be aborted.

       Similarly, the 'postconnect' keyword similarly allows you to specify  a
       shell  command to be executed just after	each time a mailserver connec-
       tion is taken down.

       The 'forcecr' option controls whether lines terminated by LF  only  are
       given CRLF termination before forwarding.  Strictly speaking RFC821 re-
       quires this, but	few MTAs enforce the requirement  so  this  option  is
       normally	 off  (only one	such MTA, qmail, is in significant use at time
       of writing).

       The 'stripcr' option controls whether carriage returns are stripped out
       of retrieved mail before	it is forwarded.  It is	normally not necessary
       to set this, because it defaults	to 'on'	(CR  stripping	enabled)  when
       there  is  an  MDA declared but 'off' (CR stripping disabled) when for-
       warding is via SMTP.  If	'stripcr' and 'forcecr'	are both on, 'stripcr'
       will override.

       The 'pass8bits' option exists to	cope with Microsoft mail programs that
       stupidly	slap a "Content-Transfer-Encoding: 7bit" on everything.	  With
       this  option off	(the default) and such a header	present, fetchmail de-
       clares BODY=7BIT	to an ESMTP-capable listener; this causes problems for
       messages	 actually  using 8-bit ISO or KOI-8 character sets, which will
       be garbled by having the	high bits  of  all  characters	stripped.   If
       'pass8bits'  is on, fetchmail is	forced to declare BODY=8BITMIME	to any
       ESMTP-capable listener.	If the listener	is 8-bit-clean (as all the ma-
       jor ones	now are) the right thing will probably result.

       The 'dropstatus'	option controls	whether	nonempty Status	and X-Mozilla-
       Status lines are	retained in fetched mail (the default)	or  discarded.
       Retaining  them	allows	your  MUA  to  see what	messages (if any) were
       marked seen on the server.  On the other	hand, it can confuse some new-
       mail notifiers, which assume that anything with a Status	line in	it has
       been seen.  (Note: the empty Status lines inserted by  some  buggy  POP
       servers are unconditionally discarded.)

       The  'dropdelivered'  option controls whether Delivered-To headers will
       be kept in fetched mail (the default) or	discarded. These  headers  are
       added by	Qmail and Postfix mailservers in order to avoid	mail loops but
       may get in your way if you try to "mirror" a mailserver within the same
       domain. Use with	caution.

       The  'mimedecode'  option  controls  whether  MIME  messages  using the
       quoted-printable	encoding are automatically converted into  pure	 8-bit
       data.  If you are delivering mail to an ESMTP-capable, 8-bit-clean lis-
       tener (that includes all	of the major MTAs like	sendmail),  then  this
       will  automatically  convert  quoted-printable message headers and data
       into 8-bit data,	making it easier to understand when reading  mail.  If
       your e-mail programs know how to	deal with MIME messages, then this op-
       tion is not needed.  The	mimedecode option is off by  default,  because
       doing  RFC2047 conversion on headers throws away	character-set informa-
       tion and	can lead to bad	results	if the encoding	of the headers differs
       from the	body encoding.

       The  'idle'  option is intended to be used with IMAP servers supporting
       the RFC2177 IDLE	command	extension, but does not	strictly  require  it.
       If it is	enabled, and fetchmail detects that IDLE is supported, an IDLE
       will be issued at the end of each poll.	This will tell the IMAP	server
       to  hold	 the  connection  open	and notify the client when new mail is
       available.  If IDLE is not supported, fetchmail will simulate it	by pe-
       riodically  issuing  NOOP.  If you need to poll a link frequently, IDLE
       can save	bandwidth by eliminating TCP/IP	connects and LOGIN/LOGOUT  se-
       quences.	 On  the other hand, an	IDLE connection	will eat almost	all of
       your fetchmail's	time, because it will never drop  the  connection  and
       allow  other  polls  to occur unless the	server times out the IDLE.  It
       also doesn't work with multiple folders;	only  the  first  folder  will
       ever be polled.

       The  'properties'  option is an extension mechanism.  It	takes a	string
       argument, which is ignored by fetchmail itself.	 The  string  argument
       may  be	used  to store configuration information for scripts which re-
       quire it.  In particular, the output of '--configdump' option will make
       properties  associated  with a user entry readily available to a	Python
       script.

   Miscellaneous Run Control Options
       The words 'here'	and 'there'  have  useful  English-like	 significance.
       Normally	 'user	eric  is esr' would mean that mail for the remote user
       'eric' is to be delivered to 'esr', but you can make  this  clearer  by
       saying 'user eric there is esr here', or	reverse	it by saying 'user esr
       here is eric there'

       Legal protocol identifiers for use with the 'protocol' keyword are:

	   auto	(or AUTO) (legacy, to be removed from future release)
	   pop2	(or POP2) (legacy, to be removed from future release)
	   pop3	(or POP3)
	   sdps	(or SDPS)
	   imap	(or IMAP)
	   apop	(or APOP)
	   kpop	(or KPOP)

       Legal authentication types are  'any',  'password',  'kerberos',	 'ker-
       beros_v4',  'kerberos_v5'  and 'gssapi',	'cram-md5', 'otp', 'msn' (only
       for POP3), 'ntlm', 'ssh', 'external' (only IMAP).  The 'password'  type
       specifies  authentication  by  normal  transmission  of a password (the
       password	may be plain text or subject to	 protocol-specific  encryption
       as  in  CRAM-MD5);  'kerberos' tells fetchmail to try to	get a Kerberos
       ticket at the start of each query instead, and send an arbitrary	string
       as the password;	and 'gssapi' tells fetchmail to	use GSSAPI authentica-
       tion.  See the description of the 'auth'	keyword	for more.

       Specifying 'kpop' sets POP3 protocol over port 1109  with  Kerberos  V4
       authentication.	These defaults may be overridden by later options.

       There  are  some	 global	option statements: 'set	logfile' followed by a
       string sets the same global specified  by  --logfile.   A  command-line
       --logfile option	will override this. Note that --logfile	is only	effec-
       tive if fetchmail detaches itself from the terminal and the logfile al-
       ready exists before fetchmail is	run, and it overrides --syslog in this
       case.  Also, 'set daemon' sets the  poll	 interval  as  --daemon	 does.
       This can	be overridden by a command-line	--daemon option; in particular
       --daemon	0 can be used to force foreground operation. The 'set postmas-
       ter'  statement	sets  the  address to which multidrop mail defaults if
       there are no local matches.  Finally, 'set syslog' sends	 log  messages
       to syslogd(8).

DEBUGGING FETCHMAIL
   Fetchmail crashing
       There are various ways in that fetchmail	may "crash", i.	e. stop	opera-
       tion suddenly and unexpectedly. A "crash" usually refers	 to  an	 error
       condition  that	the  software  did  not	handle by itself. A well-known
       failure mode is the "segmentation fault"	or "signal 11" or "SIGSEGV" or
       just  "segfault"	for short. These can be	caused by hardware or by soft-
       ware problems. Software-induced segfaults  can  usually	be  reproduced
       easily and in the same place, whereas hardware-induced segfaults	can go
       away if the computer is rebooted, or powered off	for a few  hours,  and
       can  happen  in	random locations even if you use the software the same
       way.

       For solving hardware-induced segfaults, find the	faulty	component  and
       repair  or replace it.  The Sig11 FAQ <https://www.bitwizard.nl/sig11/>
       may help	you with details.

       For solving software-induced  segfaults,	 the  developers  may  need  a
       "stack backtrace".

   Enabling fetchmail core dumps
       By  default,  fetchmail	suppresses  core  dumps	as these might contain
       passwords and other  sensitive  information.  For  debugging  fetchmail
       crashes,	 obtaining  a  "stack backtrace" from a	core dump is often the
       quickest	way to solve the problem, and when posting your	problem	 on  a
       mailing list, the developers may	ask you	for a "backtrace".

       1.  To  get  useful backtraces, fetchmail needs to be installed without
       getting stripped	of its compilation symbols.  Unfortunately,  most  bi-
       nary packages that are installed	are stripped, and core files from sym-
       bol-stripped programs are worthless.  So	 you  may  need	 to  recompile
       fetchmail. On many systems, you can type

	       file `which fetchmail`

       to  find	 out if	fetchmail was symbol-stripped or not. If yours was un-
       stripped, fine, proceed,	if it was stripped, you	need to	recompile  the
       source  code first. You do not usually need to install fetchmail	in or-
       der to debug it.

       2. The shell environment	that starts fetchmail  needs  to  enable  core
       dumps.  The  key	 is the	"maximum core (file) size" that	can usually be
       configured with a tool named "limit" or "ulimit". See the documentation
       for  your shell for details. In the popular bash	shell, "ulimit -Sc un-
       limited"	will allow the core dump.

       3. You need to tell fetchmail, too, to allow core dumps.	 To  do	 this,
       run  fetchmail with the -d0 -v options.	It is often easier to also add
       --nosyslog -N as	well.

       Finally,	you need to reproduce the crash. You can just start  fetchmail
       from  the directory where you compiled it by typing ./fetchmail,	so the
       complete	command	line will start	with ./fetchmail -Nvd0 --nosyslog  and
       perhaps list your other options.

       After the crash,	run your debugger to obtain the	core dump.  The	debug-
       ger will	often be GNU GDB, you can then type (adjust  paths  as	neces-
       sary) gdb ./fetchmail fetchmail.core and	then, after GDB	has started up
       and read	all its	files, type backtrace full, save the  output  (copy  &
       paste  will  do,	 the  backtrace	will be	read by	a human) and then type
       quit to leave gdb.  Note: on some systems, the core files have  differ-
       ent  names, they	might contain a	number instead of the program name, or
       number and name,	but it will usually have "core"	as part	of their name.

INTERACTION WITH RFC 822
       When trying to determine	the originating	address	of a  message,	fetch-
       mail looks through headers in the following order:

	       Return-Path:
	       Resent-Sender: (ignored if it doesn't contain an	@ or !)
	       Sender: (ignored	if it doesn't contain an @ or !)
	       Resent-From:
	       From:
	       Reply-To:
	       Apparently-From:

       The  originating	 address is used for logging, and to set the MAIL FROM
       address when forwarding to SMTP.	 This order is intended	to cope	grace-
       fully  with  receiving mailing list messages in multidrop mode. The in-
       tent is that if a local address doesn't exist, the bounce message won't
       be  returned blindly to the author or to	the list itself, but rather to
       the list	manager	(which is less annoying).

       In multidrop mode, destination headers are processed as follows:	First,
       fetchmail  looks	 for  the header specified by the 'envelope' option in
       order to	determine the local recipient address.	If  the	 mail  is  ad-
       dressed to more than one	recipient, the Received	line won't contain any
       information regarding recipient addresses.

       Then fetchmail looks for	the Resent-To:,	 Resent-Cc:,  and  Resent-Bcc:
       lines.	If  they  exist,  they should contain the final	recipients and
       have precedence over their To:/Cc:/Bcc: counterparts.  If the  Resent-*
       lines  don't  exist,  the  To:,	Cc:, Bcc: and Apparently-To: lines are
       looked for. (The	presence of a Resent-To: is taken to  imply  that  the
       person  referred	 by  the To: address has already received the original
       copy of the mail.)

CONFIGURATION EXAMPLES
       Note that although there	are password declarations in a	good  many  of
       the  examples below, this is mainly for illustrative purposes.  We rec-
       ommend stashing account/password	pairs in your $HOME/.netrc file, where
       they  can  be  used  not	just by	fetchmail but by ftp(1)	and other pro-
       grams.

       The basic format	is:

	      poll SERVERNAME protocol PROTOCOL	username NAME  password	 PASS-
	      WORD

       Example:

	      poll pop.provider.net protocol pop3 username "jsmith" password "secret1"

       Or, using some abbreviations:

	      poll pop.provider.net proto pop3 user "jsmith" password "secret1"

       Multiple	servers	may be listed:

	      poll pop.provider.net proto pop3 user "jsmith" pass "secret1"
	      poll other.provider.net proto pop2 user "John.Smith" pass	"My^Hat"

       Here's the same version with more whitespace and	some noise words:

	      poll pop.provider.net proto pop3
		   user	"jsmith", with password	secret1, is "jsmith" here;
	      poll other.provider.net proto pop2:
		   user	"John.Smith", with password "My^Hat", is "John.Smith" here;

       If  you	need  to include whitespace in a parameter string or start the
       latter with a number, enclose the string	in double quotes.  Thus:

	      poll mail.provider.net with proto	pop3:
		   user	"jsmith" there has password "4u	but u can't krak this"
		   is jws here and wants mda "/bin/mail"

       You may have an initial server description headed by the	 keyword  'de-
       faults'	instead	of 'poll' followed by a	name.  Such a record is	inter-
       preted as defaults for all queries to use. It may be overwritten	by in-
       dividual	server descriptions.  So, you could write:

	      defaults proto pop3
		   user	"jsmith"
	      poll pop.provider.net
		   pass	"secret1"
	      poll mail.provider.net
		   user	"jjsmith" there	has password "secret2"

       It's  possible  to  specify  more than one user per server.  The	'user'
       keyword leads off a user	description, and every user specification in a
       multi-user entry	must include it.  Here's an example:

	      poll pop.provider.net proto pop3 port 3111
		   user	"jsmith" with pass "secret1" is	"smith"	here
		   user	jones with pass	"secret2" is "jjones" here keep

       This  associates	 the  local username 'smith' with the pop.provider.net
       username	 'jsmith'  and	the   local   username	 'jjones'   with   the
       pop.provider.net	 username  'jones'.   Mail  for	'jones'	is kept	on the
       server after download.

       Here's what a simple retrieval configuration for	 a  multidrop  mailbox
       looks like:

	      poll pop.provider.net:
		   user	maildrop with pass secret1 to golux 'hurkle'='happy' snark here

       This  says  that	 the  mailbox of account 'maildrop' on the server is a
       multidrop box, and that messages	in it should be	parsed for the	server
       user  names  'golux', 'hurkle', and 'snark'.  It	further	specifies that
       'golux' and 'snark' have	the same name on the client as on the  server,
       but  mail  for  server user 'hurkle' should be delivered	to client user
       'happy'.

       Note that fetchmail, until version 6.3.4, did NOT allow	full  user@do-
       main specifications here, these would never match.  Fetchmail 6.3.5 and
       newer support user@domain specifications	on the	left-hand  side	 of  a
       user mapping.

       Here's an example of another kind of multidrop connection:

	      poll pop.provider.net localdomains loonytoons.org	toons.org
		   envelope X-Envelope-To
		   user	maildrop with pass secret1 to *	here

       This  also says that the	mailbox	of account 'maildrop' on the server is
       a multidrop box.	 It tells fetchmail that any  address  in  the	loony-
       toons.org  or  toons.org	 domains  (including sub-domain	addresses like
       'joe@daffy.loonytoons.org') should be passed through to the local  SMTP
       listener	 without  modification.	  Be  careful  of mail loops if	you do
       this!

       Here's an example configuration using ssh and the plugin	 option.   The
       queries	are  made  directly  on	the stdin and stdout of	imapd via ssh.
       Note that in this setup,	IMAP authentication can	be skipped.

	      poll mailhost.net	with proto imap:
		   plugin "ssh %h /usr/sbin/imapd" auth	ssh;
		   user	esr is esr here

THE USE	AND ABUSE OF MULTIDROP MAILBOXES
       Use the multiple-local-recipients feature with caution -- it can	 bite.
       All multidrop features are ineffective in ETRN and ODMR modes.

       Also,  note  that  in multidrop mode duplicate mails are	suppressed.  A
       piece of	mail is	considered duplicate if	it has the same	message-ID  as
       the  message  immediately  preceding and	more than one addressee.  Such
       runs of messages	may be generated when copies of	a message addressed to
       multiple	users are delivered to a multidrop box.

   Header vs. Envelope addresses
       The  fundamental	problem	is that	by having your mailserver toss several
       peoples'	mail in	a single maildrop box, you may have thrown away	poten-
       tially  vital information about who each	piece of mail was actually ad-
       dressed to (the 'envelope address', as opposed to the header  addresses
       in the RFC822 To/Cc headers - the Bcc is	not available at the receiving
       end).  This 'envelope address' is the address  you  need	 in  order  to
       reroute mail properly.

       Sometimes fetchmail can deduce the envelope address.  If	the mailserver
       MTA is sendmail and the item of mail had	just one  recipient,  the  MTA
       will  have  written a 'by/for' clause that gives	the envelope addressee
       into its	Received header. But this  doesn't  work  reliably  for	 other
       MTAs,  nor  if there is more than one recipient.	 By default, fetchmail
       looks for envelope addresses in these lines; you	can restore  this  de-
       fault with -E "Received"	or 'envelope Received'.

       As a better alternative,	some SMTP listeners and/or mail	servers	insert
       a header	in each	message	containing a copy of the  envelope  addresses.
       This  header  (when it exists) is often 'X-Original-To',	'Delivered-To'
       or 'X-Envelope-To'.  Fetchmail's	assumption about this can  be  changed
       with the	-E or 'envelope' option.  Note that writing an envelope	header
       of this kind exposes the	names of recipients (including blind-copy  re-
       cipients)  to all receivers of the messages, so the upstream must store
       one copy	of the message per recipient to	avoid becoming a privacy prob-
       lem.

       Postfix,	 since version 2.0, writes an X-Original-To: header which con-
       tains a copy of the envelope as it was received.

       Qmail and Postfix generally write a 'Delivered-To' header upon deliver-
       ing  the	 message  to  the  mail	 spool and use it to avoid mail	loops.
       Qmail virtual domains however will prefix the user name with  a	string
       that  normally matches the user's domain. To remove this	prefix you can
       use the -Q or 'qvirtual'	option.

       Sometimes, unfortunately, neither of these methods works.  That is  the
       point  when you should contact your ISP and ask them to provide such an
       envelope	header,	and you	should not use multidrop  in  this  situation.
       When  they  all fail, fetchmail must fall back on the contents of To/Cc
       headers (Bcc headers are	not available -	see below) to try to determine
       recipient addressees -- and these are unreliable.  In particular, mail-
       ing-list	software often ships mail with only the	list broadcast address
       in the To header.

       Note that a future version of fetchmail may remove To/Cc	parsing!

       When fetchmail cannot deduce a recipient	address	that is	local, and the
       intended	recipient address was anyone other than	 fetchmail's  invoking
       user,  mail  will  get  lost.  This is what makes the multidrop feature
       risky without proper envelope information.

       A related problem is that when you blind-copy a mail message,  the  Bcc
       information  is carried only as envelope	address	(it's removed from the
       headers by the sending mail server, so fetchmail	can  see  it  only  if
       there  is an X-Envelope-To header).  Thus, blind-copying	to someone who
       gets mail over a	fetchmail multidrop link  will	fail  unless  the  the
       mailserver  host	routinely writes X-Envelope-To or an equivalent	header
       into messages in	your maildrop.

       In conclusion, mailing lists and	Bcc'd mail can only work if the	server
       you're fetching from

       (1)    stores one copy of the message per recipient in your domain and

       (2)    records  the  envelope information in a special header (X-Origi-
	      nal-To, Delivered-To, X-Envelope-To).

   Good	Ways To	Use Multidrop Mailboxes
       Multiple	local names can	be used	to administer a	mailing	list from  the
       client side of a	fetchmail collection.  Suppose your name is 'esr', and
       you want	to both	pick up	your own mail  and  maintain  a	 mailing  list
       called  (say)  "fetchmail-friends", and you want	to keep	the alias list
       on your client machine.

       On your server, you can alias 'fetchmail-friends' to  'esr';  then,  in
       your .fetchmailrc, declare 'to esr fetchmail-friends here'.  Then, when
       mail including 'fetchmail-friends' as a local address gets fetched, the
       list name will be appended to the list of recipients your SMTP listener
       sees.  Therefore	it will	undergo	alias expansion	locally.  Be  sure  to
       include	'esr'  in  the	local alias expansion of fetchmail-friends, or
       you'll never see	mail sent only to the list.  Also be  sure  that  your
       listener	 has the "me-too" option set (sendmail's -oXm command-line op-
       tion or OXm declaration)	so your	name isn't removed from	 alias	expan-
       sions in	messages you send.

       This  trick  is not without its problems, however.  You'll begin	to see
       this when a message comes in that is addressed only to a	 mailing  list
       you  do not have	declared as a local name.  Each	such message will fea-
       ture an 'X-Fetchmail-Warning' header which is generated because	fetch-
       mail  cannot  find a valid local	name in	the recipient addresses.  Such
       messages	default	(as was	described above) to being sent	to  the	 local
       user  running fetchmail,	but the	program	has no way to know that	that's
       actually	the right thing.

   Bad Ways To Abuse Multidrop Mailboxes
       Multidrop mailboxes and fetchmail serving multiple users	in daemon mode
       do not mix.  The	problem, again,	is mail	from mailing lists, which typ-
       ically does not have an individual recipient address  on	 it.	Unless
       fetchmail can deduce an envelope	address, such mail will	only go	to the
       account running fetchmail (probably root).   Also,  blind-copied	 users
       are very	likely never to	see their mail at all.

       If  you're tempted to use fetchmail to retrieve mail for	multiple users
       from a single mail drop via POP or IMAP,	think again  (and  reread  the
       section	on  header and envelope	addresses above).  It would be smarter
       to just let the mail sit	in the mailserver's queue and use  fetchmail's
       ETRN  or	ODMR modes to trigger SMTP sends periodically (of course, this
       means you have to poll more frequently than the mailserver's expiry pe-
       riod).  If you can't arrange this, try setting up a UUCP	feed.

       If  you	absolutely must	use multidrop for this purpose,	make sure your
       mailserver writes an envelope-address header that  fetchmail  can  see.
       Otherwise you will lose mail and	it will	come back to haunt you.

   Speeding Up Multidrop Checking
       Normally, when multiple users are declared fetchmail extracts recipient
       addresses as described above and	checks each host part with DNS to  see
       if it's an alias	of the mailserver.  If so, the name mappings described
       in the "to ... here" declaration	are done and the mail  locally	deliv-
       ered.

       This is a convenient but	also slow method.  To speed it up, pre-declare
       mailserver aliases with 'aka'; these are	checked	before DNS lookups are
       done.   If you're certain your aka list contains	all DNS	aliases	of the
       mailserver (and all MX names pointing at	it - note this may change in a
       future  version)	 you  can declare 'no dns' to suppress DNS lookups en-
       tirely and only match against the aka list.

SOCKS
       Support for socks4/5 is a compile time configuration option. Once  com-
       piled  in, fetchmail will always	use the	socks libraries	and configura-
       tion on your system, there are no run-time switches in fetchmail	-  but
       you  can	 still configure SOCKS:	you can	specify	which SOCKS configura-
       tion file is used in the	SOCKS_CONF environment variable.

       For instance, if	you wanted to bypass the SOCKS	proxy  altogether  and
       have    fetchmail    connect    directly,    you	   could   just	  pass
       SOCKS_CONF=/dev/null in the environment,	for example  (add  your	 usual
       command line options - if any - to the end of this line):

       env SOCKS_CONF=/dev/null	fetchmail

EXIT CODES
       To  facilitate  the  use	 of fetchmail in shell scripts,	an exit	status
       code is returned	to give	an indication of what occurred during a	 given
       connection.

       The exit	codes returned by fetchmail are	as follows:

       0      One  or more messages were successfully retrieved	(or, if	the -c
	      option was selected, were	found waiting but not retrieved).

       1      There was	no mail	awaiting retrieval.  (There may	have been  old
	      mail still on the	server but not selected	for retrieval.)	If you
	      do not want "no mail" to be an error  condition  (for  instance,
	      for cron jobs), use a POSIX-compliant shell and add

	      || [ $? -eq 1 ]

	      to  the end of the fetchmail command line, note that this	leaves
	      0	untouched, maps	1 to 0,	and maps all other  codes  to  1.  See
	      also item	#C8 in the FAQ.

       2      An error was encountered when attempting to open a socket	to re-
	      trieve mail.  If you don't know what a socket  is,  don't	 worry
	      about  it	 -- just treat this as an 'unrecoverable error'.  This
	      error can	also be	because	a protocol fetchmail wants to  use  is
	      not listed in /etc/services.

       3      The  user	authentication step failed.  This usually means	that a
	      bad user-id, password, or	APOP id	was specified.	Or it may mean
	      that you tried to	run fetchmail under circumstances where	it did
	      not have standard	input attached to a  terminal  and  could  not
	      prompt for a missing password.

       4      Some sort	of fatal protocol error	was detected.

       5      There  was  a  syntax  error in the arguments to fetchmail, or a
	      pre- or post-connect command failed.

       6      The run control file had bad permissions.

       7      There was	an error condition reported by the server.   Can  also
	      fire if fetchmail	timed out while	waiting	for the	server.

       8      Client-side  exclusion error.  This means	fetchmail either found
	      another copy of itself already running, or failed	in such	a  way
	      that it isn't sure whether another copy is running.

       9      The user authentication step failed because the server responded
	      "lock busy".  Try	again after a brief pause!  This error is  not
	      implemented  for all protocols, nor for all servers.  If not im-
	      plemented	for your server, "3" will  be  returned	 instead,  see
	      above.  May be returned when talking to qpopper or other servers
	      that can respond with "lock busy"	or some	similar	text  contain-
	      ing the word "lock".

       10     The fetchmail run	failed while trying to do an SMTP port open or
	      transaction.

       11     Fatal DNS	error.	Fetchmail encountered an error while  perform-
	      ing a DNS	lookup at startup and could not	proceed.

       12     BSMTP batch file could not be opened.

       13     Poll terminated by a fetch limit (see the	--fetchlimit option).

       14     Server busy indication.

       23     Internal error.  You should see a	message	on standard error with
	      details.

       24 - 26,	28, 29
	      These are	internal codes and should not appear externally.

       When fetchmail queries more than	one host, return status	is  0  if  any
       query  successfully retrieved mail. Otherwise the returned error	status
       is that of the last host	queried.

FILES
       ~/.fetchmailrc, $HOME/.fetchmailrc, $HOME_ETC/.fetchmailrc, $FETCHMAIL-
       HOME/fetchmailrc
	    default run	control	file (location can be overridden with environ-
	    ment variables)

       ~/.fetchids,    $HOME/.fetchids,	   $HOME_ETC/.fetchids,	   $FETCHMAIL-
       HOME/.fetchids
	    default  location  of  file	 recording  last message UIDs seen per
	    host.  (location can be overridden with environment	variables)

       ~/.fetchmail.pid,    $HOME/.fetchmail.pid,    $HOME_ETC/.fetchmail.pid,
       $FETCHMAILHOME/fetchmail.pid
	    default  location  of  lock	 file  to help prevent concurrent runs
	    (non-root mode).  (location	can  be	 overridden  with  environment
	    variables)

       ~/.netrc, $HOME/.netrc, $HOME_ETC/.netrc
	    your FTP run control file, which (if present) will be searched for
	    passwords as a last	resort before prompting	for one	interactively.
	    (location can be overridden	with environment variables)

       /var/run/fetchmail.pid
	    lock  file	to help	prevent	concurrent runs	(root mode, Linux sys-
	    tems).

       /etc/fetchmail.pid
	    lock file to help prevent  concurrent  runs	 (root	mode,  systems
	    without /var/run).

ENVIRONMENT
       FETCHMAILHOME
	      If  this environment variable is set to a	valid and existing di-
	      rectory name,  fetchmail	will  read  $FETCHMAILHOME/fetchmailrc
	      (the  dot	 is  missing  in  this case), $FETCHMAILHOME/.fetchids
	      (keeping its dot)	and $FETCHMAILHOME/fetchmail.pid (without dot)
	      rather  than from	the user's home	directory.  The	.netrc file is
	      always looked for	in the the invoking user's home	directory  (or
	      $HOME_ETC) regardless of FETCHMAILHOME's setting.

       FETCHMAILUSER
	      If  this	environment variable is	set, it	is used	as the name of
	      the calling user (default	local name) for	purposes such as mail-
	      ing  error  notifications.   Otherwise, if either	the LOGNAME or
	      USER variable is	correctly  set	(e.g.  the  corresponding  UID
	      matches  the  session user ID) then that name is used as the de-
	      fault local name.	 Otherwise getpwuid(3) must  be	 able  to  re-
	      trieve a password	entry for the session ID (this elaborate logic
	      is designed to handle the	case  of  multiple  names  per	userid
	      gracefully).

       FETCHMAIL_DISABLE_CBC_IV_COUNTERMEASURE
	      (since  v6.3.22):	 If  this  environment variable	is set and not
	      empty, fetchmail will disable a countermeasure  against  an  SSL
	      CBC  IV  attack (by setting SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS).
	      This is a	security risk, but may be necessary for	connecting  to
	      certain  non-standards-conforming	servers.  See fetchmail's NEWS
	      file and fetchmail-SA-2012-01.txt	for details.   Earlier	fetch-
	      mail  versions (v6.3.21 and older) used to disable this counter-
	      measure, but v6.3.22 no longer does that as a safety precaution.

       FETCHMAIL_POP3_FORCE_RETR
	      (since v6.3.9): If this environment variable is defined  at  all
	      (even  if	 empty), fetchmail will	forgo the POP3 TOP command and
	      always use RETR. This can	be used	as a workaround	when TOP  does
	      not work properly.

       FETCHMAIL_INCLUDE_DEFAULT_X509_CA_CERTS
	      (since  v6.3.17):	 If  this  environment variable	is set and not
	      empty, fetchmail will always load	the default X.509 trusted cer-
	      tificate	 locations   for  SSL/TLS  CA  certificates,  even  if
	      --sslcertfile and	--sslcertpath are given.  The latter locations
	      take precedence over the system default locations.  This is use-
	      ful in case there	are broken certificates	in the system directo-
	      ries  and	the user has no	administrator privileges to remedy the
	      problem.

       HOME   (documented since	6.4.1):	This variable is nomally  set  to  the
	      user's  home  directory.	If  it is set to a different directory
	      than what	is the password	database, HOME takes precedence.

       HOME_ETC
	      (documentation corrected to match	behaviour code	since  6.4.1):
	      If  the  HOME_ETC	 variable is set, it will override fetchmail's
	      idea  of	$HOME,	i.  e.	fetchmail  will	  read	 .fetchmailrc,
	      .fetchids,  .fetchmail.pid  and .netrc from $HOME_ETC instead of
	      $HOME (or	if HOME	is also	unset, from the	passwd file's home di-
	      rectory location).

	      If  HOME_ETC and FETCHMAILHOME are both set, FETCHMAILHOME takes
	      prececence and HOME_ETC will be ignored.

       SOCKS_CONF
	      (only if SOCKS support is	compiled in) this variable is used  by
	      the socks	library	to find	out which configuration	file it	should
	      read. Set	this to	/dev/null to bypass the	SOCKS proxy.

SIGNALS
       If a fetchmail daemon is	running	as root, SIGUSR1 wakes it up from  its
       sleep  phase and	forces a poll of all non-skipped servers. For compati-
       bility reasons, SIGHUP can also be used in 6.3.X	but may	not be	avail-
       able in future fetchmail	versions.

       If fetchmail is running in daemon mode as non-root, use SIGUSR1 to wake
       it (this	is so SIGHUP due to logout can retain the  default  action  of
       killing it).

       Running fetchmail in foreground while a background fetchmail is running
       will do whichever of these is appropriate to wake it up.

BUGS, LIMITATIONS, AND KNOWN PROBLEMS
       Please check the	NEWS file that shipped with fetchmail for  more	 known
       bugs than those listed here.

       Fetchmail  cannot  handle  user	names  that contain blanks after a "@"
       character, for instance "demonstr@ti on". These are rather uncommon and
       only  hurt when using UID-based --keep setups, so the 6.3.X versions of
       fetchmail won't be fixed.

       Fetchmail cannot	handle configurations where you	have multiple accounts
       that  use the same server name and the same login. Any user@server com-
       bination	must be	unique.

       The assumptions that the	DNS and	in particular the  checkalias  options
       make  are  not  often sustainable. For instance,	it has become uncommon
       for an MX server	to be a	POP3 or	IMAP server at the same	 time.	There-
       fore the	MX lookups may go away in a future release.

       The  mda	 and plugin options interact badly.  In	order to collect error
       status from the MDA, fetchmail has to change its	normal signal handling
       so  that	 dead  plugin  processes don't get reaped until	the end	of the
       poll cycle.  This can cause resource starvation if too many zombies ac-
       cumulate.  So either don't deliver to a MDA using plugins or risk being
       overrun by an army of undead.

       The --interface option does not support IPv6 and	it is doubtful	if  it
       ever  will,  since there	is no portable way to query interface IPv6 ad-
       dresses.

       The RFC822 address parser used in multidrop mode	chokes on  some	 @-ad-
       dresses	that are technically legal but bizarre.	 Strange uses of quot-
       ing and embedded	comments are likely to confuse it.

       In a message with multiple envelope headers, only  the  last  one  pro-
       cessed will be visible to fetchmail.

       Use  of	some  of  these	protocols requires that	the program send unen-
       crypted passwords over the TCP/IP connection to the  mailserver.	  This
       creates a risk that name/password pairs might be	snaffled with a	packet
       sniffer or more sophisticated monitoring	 software.   Under  Linux  and
       FreeBSD,	 the  --interface  option  can	be used	to restrict polling to
       availability of a specific interface device with	a  specific  local  or
       remote  IP  address,  but snooping is still possible if (a) either host
       has a network device that can be	opened in promiscuous mode, or (b) the
       intervening network link	can be tapped.	We recommend the use of	ssh(1)
       tunnelling to not only shroud your passwords  but  encrypt  the	entire
       conversation.

       Use  of	the  %F	 or  %T	escapes	in an mda option could open a security
       hole, because they pass text manipulable	by an attacker to a shell com-
       mand.  Potential	shell characters are replaced by '_' before execution.
       The hole	is further reduced by the fact that fetchmail temporarily dis-
       cards any suid privileges it may	have while running the MDA.  For maxi-
       mum safety, however, don't use an mda command containing	%F or %T  when
       fetchmail is run	from the root account itself.

       Fetchmail's  method  of	sending	bounces	due to errors or spam-blocking
       and spam	bounces	requires that port 25 of localhost  be	available  for
       sending mail via	SMTP.

       If you modify ~/.fetchmailrc while a background instance	is running and
       break the syntax, the background	instance will die silently.   Unfortu-
       nately,	it  can't die noisily because we don't yet know	whether	syslog
       should be enabled.  On some systems, fetchmail  dies  quietly  even  if
       there is	no syntax error; this seems to have something to do with buggy
       terminal	ioctl code in the kernel.

       The -f -	option (reading	a configuration	from  stdin)  is  incompatible
       with the	plugin option.

       The 'principal' option only handles Kerberos IV,	not V.

       Interactively  entered  passwords are truncated after 63	characters. If
       you really need to use a	longer password, you will have to use  a  con-
       figuration file.

       A  backslash  as	 the  last  character  of a configuration file will be
       flagged as a syntax error rather	than ignored.

       The BSMTP error handling	is virtually nonexistent and may leave	broken
       messages	behind.

       Send comments, bug reports, gripes, and the like	to the fetchmail-devel
       list <fetchmail-devel@lists.sourceforge.net>

       An HTML	FAQ  <https://fetchmail.sourceforge.io/fetchmail-FAQ.html>  is
       available at the	fetchmail home page, it	should also accompany your in-
       stallation.

AUTHOR
       Fetchmail is currently maintained by Matthias Andree and	Rob Funk  with
       major  assistance  from	Sunil Shetye (for code)	and Rob	MacGregor (for
       the mailing lists).

       Most of the code	is from	Eric S.	Raymond	<esr@snark.thyrsus.com>	.  Too
       many other people to name here have contributed code and	patches.

       This  program  is descended from	and replaces popclient,	by Carl	Harris
       <ceharris@mal.com> ; the	internals have	become	quite  different,  but
       some  of	 its  interface	design is directly traceable to	that ancestral
       program.

       This manual page	has been improved by Matthias Andree, R. Hannes	 Bein-
       ert, and	Hector Garcia.

SEE ALSO
       README, README.SSL, README.SSL-SERVER, The Fetchmail FAQ	<https://
       www.fetchmail.info/fetchmail-FAQ.html>, mutt(1),	elm(1),	mail(1), send-
       mail(8),	popd(8), imapd(8), netrc(5).

       The fetchmail home page.	 <https://www.fetchmail.info/>

       The fetchmail home page (alternative URI).  <https://
       fetchmail.sourceforge.io/>

       The maildrop home page.	<https://www.courier-mta.org/maildrop/>

APPLICABLE STANDARDS
       Note that this list is just a collection	of references and not a	state-
       ment  as	 to  the actual	protocol conformance or	requirements in	fetch-
       mail.

       SMTP/ESMTP:
	    RFC	821, RFC 2821, RFC 1869, RFC 1652, RFC	1870,  RFC  1983,  RFC
	    1985, RFC 2554.

       mail:
	    RFC	822, RFC 2822, RFC 1123, RFC 1892, RFC 1894.

       POP2:
	    RFC	937

       POP3:
	    RFC	 1081,	RFC  1225, RFC 1460, RFC 1725, RFC 1734, RFC 1939, RFC
	    1957, RFC 2195, RFC	2449.

       APOP:
	    RFC	1939.

       RPOP:
	    RFC	1081, RFC 1225.

       IMAP2/IMAP2BIS:
	    RFC	1176, RFC 1732.

       IMAP4/IMAP4rev1:
	    RFC	1730, RFC 1731,	RFC 1732, RFC 2060, RFC	2061,  RFC  2195,  RFC
	    2177, RFC 2683.

       ETRN:
	    RFC	1985.

       ODMR/ATRN:
	    RFC	2645.

       OTP: RFC	1938.

       LMTP:
	    RFC	2033.

       GSSAPI:
	    RFC	1508, RFC 1734,	Generic	Security Service Application Program
	    Interface (GSSAPI)/Kerberos/Simple Authentication and Security
	    Layer (SASL) Service Names <https://www.iana.org/assignments/
	    gssapi-service-names/>.

       TLS: RFC	2595.

fetchmail 6.4.10		  2020-07-09			  fetchmail(1)

NAME | SYNOPSIS | DESCRIPTION | GENERAL OPERATION | USER AUTHENTICATION AND ENCRYPTION | POP3 VARIANTS | ALTERNATE AUTHENTICATION FORMS | DAEMON MODE | ADMINISTRATIVE OPTIONS | RETRIEVAL FAILURE MODES | SPAM FILTERING | SMTP/ESMTP ERROR HANDLING | THE RUN CONTROL FILE | DEBUGGING FETCHMAIL | INTERACTION WITH RFC 822 | CONFIGURATION EXAMPLES | THE USE AND ABUSE OF MULTIDROP MAILBOXES | SOCKS | EXIT CODES | FILES | ENVIRONMENT | SIGNALS | BUGS, LIMITATIONS, AND KNOWN PROBLEMS | AUTHOR | SEE ALSO | APPLICABLE STANDARDS

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