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BOOTPTAB(5)		  FreeBSD File Formats Manual		   BOOTPTAB(5)

     bootptab -- Internet Bootstrap Protocol server database

     The bootptab file is the configuration database file for bootpd(8), the
     Internet Bootstrap	Protocol server.  Its format is	similar	to that	of
     termcap(5)	in which two-character case-sensitive tag symbols are used to
     represent host parameters.	 These parameter declarations are separated by
     colons (:), with a	general	format of:

	   hostname:tg=value. .	. :tg=value. . . :tg=value. . .	.

     where hostname is the actual name of a bootp client (or a "dummy entry"),
     and tg is a two-character tag symbol.  Dummy entries have an invalid
     hostname (one with	a "." as the first character) and are used to provide
     default values used by other entries via the tc=.dummy-entry mechanism.
     Most tags must be followed	by an equals-sign and a	value as above.	 Some
     may also appear in	a boolean form with no value (i.e. :tg:).  The cur-
     rently recognized tags are:

     bf	  Bootfile
     bs	  Bootfile size	in 512-octet blocks
     cs	  Cookie server	address	list
     df	  Merit	dump file
     dn	  Domain name
     ds	  Domain name server address list
     ef	  Extension file
     gw	  Gateway address list
     ha	  Host hardware	address
     hd	  Bootfile home	directory
     hn	  Send client's	hostname to client
     ht	  Host hardware	type (see Assigned Numbers RFC)
     im	  Impress server address list
     ip	  Host IP address
     lg	  Log server address list
     lp	  LPR server address list
     ns	  IEN-116 name server address list
     nt	  NTP (time) Server (RFC 1129)
     ra	  Reply	address	override
     rl	  Resource location protocol server address list
     rp	  Root path to mount as	root
     sa	  TFTP server address client should use
     sm	  Host subnet mask
     sw	  Swap server address
     tc	  Table	continuation (points to	similar	"template" host	entry)
     td	  TFTP root directory used by "secure" TFTP servers
     to	  Time offset in seconds from UTC
     ts	  Time server address list
     vm	  Vendor magic cookie selector
     yd	  YP (NIS) domain name
     ys	  YP (NIS) server address

     There is also a generic tag, Tn, where n is an RFC1084 vendor field tag
     number.  Thus it is possible to immediately take advantage	of future ex-
     tensions to RFC1084 without being forced to modify	bootpd first.  Generic
     data may be represented as	either a stream	of hexadecimal numbers or as a
     quoted string of ASCII characters.	 The length of the generic data	is au-
     tomatically determined and	inserted into the proper field(s) of the
     RFC1084-style bootp reply.

     The following tags	take a whitespace-separated list of IP addresses: cs,
     ds, gw, im, lg, lp, ns, nt, ra, rl, and ts.  The ip, sa, sw, sm, and ys
     tags each take a single IP	address.  All IP addresses are specified in
     standard Internet "dot" notation and may use decimal, octal, or hexadeci-
     mal numbers (octal	numbers	begin with 0, hexadecimal numbers begin	with
     '0x' or '0X').  Any IP addresses may alternatively	be specified as	a
     hostname, causing bootpd to lookup	the IP address for that	host name us-
     ing gethostbyname(3).  If the ip tag is not specified, bootpd will	deter-
     mine the IP address using the entry name as the host name.	 (Dummy	en-
     tries use an invalid host name to avoid automatic IP lookup.)

     The ht tag	specifies the hardware type code as either an unsigned deci-
     mal, octal, or hexadecimal	integer	or one of the following	symbolic
     names: ethernet or	ether for 10Mb Ethernet, ethernet3 or ether3 for 3Mb
     experimental Ethernet, ieee802, tr, or token-ring for IEEE	802 networks,
     pronet for	Proteon	ProNET Token Ring, or chaos, arcnet, or	ax.25 for
     Chaos, ARCNET, and	AX.25 Amateur Radio networks, respectively.  The ha
     tag takes a hardware address which	may be specified as a host name	or in
     numeric form.  Note that the numeric form must be specified in hexadeci-
     mal; optional periods and/or a leading '0x' may be	included for readabil-
     ity.  The ha tag must be preceded by the ht tag (either explicitly	or im-
     plicitly; see tc below).  If the hardware address is not specified	and
     the type is specified as either "ethernet"	or "ieee802", then bootpd will
     try to determine the hardware address using ether_hostton(3).

     The hostname, home	directory, and bootfile	are ASCII strings which	may be
     optionally	surrounded by double quotes (").  The client's request and the
     values of the hd and bf symbols determine how the server fills in the
     bootfile field of the bootp reply packet.

     If	the client provides a file name	it is left as is.  Otherwise, if the
     bf	option is specified its	value is copied	into the reply packet.	If the
     hd	option is specified as well, its value is prepended to the boot	file
     copied into the reply packet.  The	existence of the boot file is checked
     only if the bs=auto option	is used	(to determine the boot file size).  A
     reply may be sent whether or not the boot file exists.

     Some newer	versions of tftpd(8) provide a security	feature	to change
     their root	directory using	the chroot(2) system call.  The	td tag may be
     used to inform bootpd of this special root	directory used by tftpd.  (One
     may alternatively use the bootpd -c chdir option.)	 The hd	tag is actu-
     ally relative to the root directory specified by the td tag.  For exam-
     ple, if the real absolute path to your BOOTP client bootfile is
     /tftpboot/bootfiles/bootimage, and	tftpd uses /tftpboot as	its "secure"
     directory,	then specify the following in bootptab:


     If	your bootfiles are located directly in /tftpboot, use:


     The sa tag	may be used to specify the IP address of the particular	TFTP
     server you	wish the client	to use.	 In the	absence	of this	tag, bootpd
     will tell the client to perform TFTP to the same machine bootpd is	run-
     ning on.

     The time offset to	may be either a	signed decimal integer specifying the
     client's time zone	offset in seconds from UTC, or the keyword auto	which
     uses the server's time zone offset.  Specifying the to symbol as a	bool-
     ean has the same effect as	specifying auto	as its value.

     The bootfile size bs may be either	a decimal, octal, or hexadecimal inte-
     ger specifying the	size of	the bootfile in	512-octet blocks, or the key-
     word auto which causes the	server to automatically	calculate the bootfile
     size at each request.  As with the	time offset, specifying	the bs symbol
     as	a boolean has the same effect as specifying auto as its	value.

     The vendor	magic cookie selector (the vm tag) may take one	of the follow-
     ing keywords: auto	(indicating that vendor	information is determined by
     the client's request), rfc1048 or rfc1084 (which always forces an
     RFC1084-style reply), or cmu (which always	forces a CMU-style reply).

     The hn tag	is strictly a boolean tag; it does not take the	usual equals-
     sign and value.  Its presence indicates that the hostname should be sent
     to	RFC1084	clients.  Bootpd attempts to send the entire hostname as it is
     specified in the configuration file; if this will not fit into the	reply
     packet, the name is shortened to just the host field (up to the first pe-
     riod, if present) and then	tried.	In no case is an arbitrarily-truncated
     hostname sent (if nothing reasonable will fit, nothing is sent).

     Often, many host entries share common values for certain tags (such as
     name servers, etc.).  Rather than repeatedly specifying these tags, a
     full specification	can be listed for one host entry and shared by others
     via the tc	(table continuation) mechanism.	 Often,	the template entry is
     a dummy host which	does not actually exist	and never sends	bootp re-
     quests.  This feature is similar to the tc	feature	of termcap(5) for sim-
     ilar terminals.  Note that	bootpd allows the tc tag symbol	to appear any-
     where in the host entry, unlike termcap which requires it to be the last
     tag.  Information explicitly specified for	a host always overrides	infor-
     mation implied by a tc tag	symbol,	regardless of its location within the
     entry.  The value of the tc tag may be the	hostname or IP address of any
     host entry	previously listed in the configuration file.

     Sometimes it is necessary to delete a specific tag	after it has been in-
     ferred via	tc.  This can be done using the	construction tag@ which	re-
     moves the effect of tag as	in termcap(5).	For example, to	completely
     undo an IEN-116 name server specification,	use :ns@: at an	appropriate
     place in the configuration	entry.	After removal with @, a	tag is eligi-
     ble to be set again through the tc	mechanism.

     Blank lines and lines beginning with "#" are ignored in the configuration
     file.  Host entries are separated from one	another	by newlines; a single
     host entry	may be extended	over multiple lines if the lines end with a
     backslash (\).  It	is also	acceptable for lines to	be longer than 80
     characters.  Tags may appear in any order,	with the following exceptions:
     the hostname must be the very first field in an entry, and	the hardware
     type must precede the hardware address.

     An	example	/etc/bootptab file follows:

	   # Sample bootptab file (

		   :ds=netserver, lancaster:\
		   :ns=pcs2, pcs1:\
		   :ts=pcs2, pcs1:\


	   # Special domain name server	and option tags	for next host
		   :T99="Special ASCII string":\



     bootpd(8),	tftpd(8)

     DARPA Internet Request For	Comments RFC951, RFC1048, RFC1084, Assigned

FreeBSD	13.0		       October 31, 1991			  FreeBSD 13.0


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