Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages


home | help
ocserv(8)		       System Management		     ocserv(8)

       ocserv -	OpenConnect VPN	server

       Openconnect  VPN	 server	 (ocserv)  is a	VPN server compatible with the
       openconnect VPN client. It follows the AnyConnect VPN protocol which is
       used by several CISCO routers.

       This a standalone server	that reads a configuration file	(see below for
       more details), and waits	for client connections.	Log messages are redi-
       rected to daemon	facility.

       The server maintains two	connections/channels with the client. The main
       VPN channel is established over TCP, HTTP and TLS. This is the  control
       channel	as  well as the	backup data channel. After its establishment a
       UDP channel using DTLS is initiated which serves	as the main data chan-
       nel.  If	 the UDP channel fails to establish or is temporarily unavail-
       able the	backup channel over TCP/TLS is being used.

       This server supports multiple authentication methods, including PAM and
       certificate authentication. Authenticated users are assigned an unpriv-
       ileged worker process and obtain	a networking (tun) device  and	an  IP
       from a configurable pool	of addresses.

       Once  authenticated,  the server	provides the client with an IP address
       and a list of routes that it may	access.	In order to  allow  high-speed
       transfers the server does not process or	filter packets.	It is expected
       that the	server has or will set up  any	required  routes  or  firewall

       It  is possible to separate users into groups, which are	either present
       on their	certificate, or	presented on login for	the  user  to  choose.
       That  way  a user may take advantage of the different settings that may
       apply per group.	See the	comments on the	configuration  file  for  more

       -f, --foreground
	      Do not fork into background.

       -d number, --debug=number
	      Enable verbose network debugging information.  This option takes
	      an integer number	as its argument.  The value of number is  con-
	      strained to being:
		  in the range	0 through 9999

       -c file,	--config=file
	      Configuration file for the server.

       -t, --test-config
	      Test the provided	configuration file.

       -p file,	--pid-file=file
	      Specify pid file for the server.

       -h, --help
	      Display usage information	and exit.

       -!, --more-help
	      Pass the extended	usage information through a pager.

       -v [{v|c|n --version [{v|c|n}]}]
	      Output version of	program	and exit.  The default mode is `v', a
	      simple version.  The `c' mode will print copyright information
	      and `n' will print the full copyright notice.

       Users can be authenticated in multiple ways, which are explained	in the
       following paragraphs. Connected users can be managed using the 'occtl'

       Password	authentication
       If your system supports Pluggable Authentication	Modules	(PAM), then
       ocserv will take	advantage of it	to password authenticate its users.
       Otherwise a plain password file similar to the UNIX password file is
       also supported.	In that	case the 'ocpasswd' tool can be	used for its
       management.  Note that password authentication can be used in conjunc-
       tion with certificate authentication.

       GSSAPI authentication
       ocserv will take	advantage of the MIT Kerberos project GSSAPI li-
       braries,	and allow authentication using any method GSSAPI supports.
       That is,	mainly,	Kerberos authentication. That is often more useful to
       be combined with	PAM or other password authentication methods so	that a
       fallback	mechanism can be used when GSSAPI fails	(e.g., when the	user
       doesn't already have a Kerberos ticket).	The GSSAPI authentication is
       implemented using SPNEGO	over HTTP (RFC4559).

       Public key (certificate)	authentication
       Public key authentication allows	the user to be authenticated by	the
       possession of the private key that corresponds to a known to the	server
       public key. That	allows the usage of common smart cards for user	au-

       In ocserv, a certificate	authority (CA) is used to sign the client cer-
       tificates. That certificate authority can be local, used	only by	the
       server to sign its user's known public keys which are then given	to
       users in	a form of certificates.	That authority need also provide a CRL
       to allow	the server to reject the revoked clients (see ca-cert, crl).

       In certificate authentication each client presents a certificate	and
       signs data provided by the server, as part of TLS authentication, to
       prove his possession of the corresponding private key.  The certificate
       need also contain user identifying information, for example, the	user
       ID of the client	must be	embedded in the	certificate's Distinguished
       Name (DN), i.e.,	in the Common Name, or UID fields. For the server to
       read the	name, the cert-user-oid	configuration option must be set.

       The following examples demonstrate how to use certtool from GnuTLS to
       generate	such CA.

       Generating the CA
	   $ certtool --generate-privkey --outfile ca-key.pem
	   $ cat << _EOF_ >ca.tmpl
	   cn =	"VPN CA"
	   organization	= "Big Corp"
	   serial = 1
	   expiration_days = -1
	   $ certtool --generate-self-signed --load-privkey ca-key.pem --template ca.tmpl --outfile ca-cert.pem

       Generating a local server certificate
       The following example generates the server key and certificate pair.
       The key generated is an RSA one,	but different types can	be used	by
       specifying the 'ecdsa' or 'dsa' options to certtool.
	   $ certtool --generate-privkey --outfile server-key.pem
	   $ cat << _EOF_ >server.tmpl
	   cn =	"VPN server"
	   dns_name = ""
	   dns_name = ""
	   #ip_address = ""
	   organization	= "MyCompany"
	   expiration_days = -1
	   encryption_key #only	if the generated key is	an RSA one
	   $ certtool --generate-certificate --load-privkey server-key.pem --load-ca-certificate ca-cert.pem --load-ca-privkey ca-key.pem --template server.tmpl --outfile server-cert.pem

       From this point the clients need	ca-cert.pem to be able to securely
       connect to the server.

       Note that it is a better	practice to use	two separate RSA keys, one
       with the	signing_key option and another with the	encryption_key.

       Generating an external CA-signed	server certificate
	   $ certtool --generate-privkey --outfile server-key.pem
	   $ cat << _EOF_ >server.tmpl
	   cn =	"My server"
	   dns_name = ""
	   organization	= "MyCompany"
	   expiration_days = -1
	   encryption_key #only	if the generated key is	an RSA one
	   $ certtool --generate-request --load-privkey	server-key.pem --template server.tmpl --outfile	server-cert.csr

       At this point you need to provide the server-cert.csr to	your CA, and
       they will send you the server certificate.

       Generating the client certificates
       Note that it is recommended to leave detailed personal information out
       of the certificate as it	is sent	in clear during	TLS authentication.
       The following process generates a certificate and converts it to	PKCS
       #12 that	is protected by	a PIN and most clients are able	to import (the
       3DES cipher is used in the example because it is	supported by far more
       devices than AES).

	   $ certtool --generate-privkey --outfile user-key.pem
	   $ cat << _EOF_ >user.tmpl
	   cn =	"user"
	   unit	= "admins"
	   expiration_days = 365
	   $ certtool --generate-certificate --load-privkey user-key.pem --load-ca-certificate ca-cert.pem --load-ca-privkey ca-key.pem	--template user.tmpl --outfile user-cert.pem

	   $ certtool --to-p12 --load-privkey user-key.pem --pkcs-cipher 3des-pkcs12 --load-certificate	user-cert.pem --outfile	user.p12 --outder

       Revoking	a client certificate
       To revoke the previous client certificate, i.e.,	preventing the user
       from accessing the VPN resources	prior to its certificate expiration,
	   $ cat << _EOF_ >crl.tmpl
	   crl_next_update = 365
	   crl_number =	1
	   $ cat user-cert.pem >>revoked.pem
	   $ certtool --generate-crl --load-ca-privkey ca-key.pem --load-ca-certificate	ca.pem --load-certificate revoked.pem --template crl.tmpl --outfile crl.pem
       After that you may want to notify ocserv	of the new CRL by using	the
       HUP signal, or wait for it to reload it.

       When there are no revoked certificates an empty revocation list should
       be generated as follows.
	   $ certtool --generate-crl --load-ca-privkey ca-key.pem --load-ca-certificate	ca.pem --template crl.tmpl --outfile crl.pem

       In certain setups, where	a firewall may be blocking ICMP	responses,
       setting the MSS of TCP connections to MTU will eliminate	the "black
       hole" connection	issues.	 See
       book.mtu-mss.html for instructions to enable it on a Linux system.

       Note that while this server utilizes privilege separation and all au-
       thentication occurs on the security module, this	does not apply for TLS
       client certificate authentication. That is due to TLS protocol limita-

       ocserv's	configuration file format
       By default, if no other file is specified, ocserv looks for its config-
       uration file at /usr/local/etc/ocserv/conf.  An example configuration
       file follows.

	   # User authentication method. Could be set multiple times and in
	   # that case all should succeed. To enable multiple methods use
	   # multiple auth directives. Available options: certificate,
	   # plain, pam, radius, gssapi.
	   # Note that authentication methods cannot be	changed	with reload.

	   # certificate:
	   #  This indicates that all connecting users must present a certificate.
	   #  The username and user group will be then extracted from it (see
	   #  cert-user-oid and	cert-group-oid). The certificate to be accepted
	   #  it must be signed	by the CA certificate as specified in 'ca-cert'	and
	   #  it must not be listed in the CRL,	as specified by	the 'crl' option.
	   # pam[gid-min=1000]:
	   #  This enabled PAM authentication of the user. The gid-min option is used
	   # by	auto-select-group option, in order to select the minimum valid group ID.
	   # plain[passwd=/usr/local/etc/ocserv/ocpasswd,otp=/usr/local/etc/ocserv/users.otp]
	   #  The plain	option requires	specifying a password file which contains
	   # entries of	the following format.
	   # "username:groupname1,groupname2:encoded-password"
	   # One entry must be listed per line,	and 'ocpasswd' should be used
	   # to	generate password entries. The 'otp' suboption allows one to specify
	   # an	oath password file to be used for one time passwords; the format of
	   # the file is described in
	   # radius[config=/etc/radiusclient/radiusclient.conf,groupconfig=true,nas-identifier=name]:
	   #  The radius option	requires specifying freeradius-client configuration
	   # file. If the groupconfig option is	set, then config-per-user/group	will be	overridden,
	   # and all configuration will	be read	from radius. That also includes	the
	   # Acct-Interim-Interval, and	Session-Timeout	values.
	   # See doc/ for the supported	radius configuration atributes.
	   # gssapi[keytab=/etc/,require-local-user-map=false,tgt-freshness-time=900,gid-min=1000]
	   #  The gssapi option	allows one to use authentication methods supported by GSSAPI,
	   # such as Kerberos tickets with ocserv. It should be	best used as an	alternative
	   # to	PAM (i.e., have	pam in auth and	gssapi in enable-auth),	to allow users with
	   # tickets and without tickets to login. The default value for require-local-user-map
	   # is	true. The 'tgt-freshness-time' if set, it would	require	the TGT	tickets	presented
	   # to	have been issued within	the provided number of seconds.	That option is used to
	   # restrict logins even if the KDC provides long time	TGT tickets.
	   # The gid-min option	is used	by auto-select-group option, in	order to select	the minimum
	   # valid group ID.

	   #auth = "certificate"
	   #auth = "pam"
	   #auth = "pam[gid-min=1000]"
	   #auth = "plain[passwd=/usr/local/etc/ocserv/ocpasswd]"
	   #auth = "radius[config=/etc/radiusclient/radiusclient.conf,groupconfig=true]"

	   # Specify alternative authentication	methods	that are sufficient
	   # for authentication. That is, if set, any of the methods enabled
	   # will be sufficient	to login.
	   #enable-auth	= "certificate"
	   #enable-auth	= "gssapi"
	   #enable-auth	= "gssapi[keytab=/etc/,require-local-user-map=true,tgt-freshness-time=900]"

	   # Accounting	methods	available:
	   # radius: can be combined with any authentication method, it	provides
	   #	  radius accounting to available users (see also stats-report-time).
	   # pam: can be combined with any authentication method, it provides
	   #	  a validation of the connecting user's	name using PAM.	It is
	   #	  superfluous to use this method when authentication is	already
	   #	  PAM.
	   # Only one accounting method	can be specified.
	   #acct = "radius[config=/etc/radiusclient/radiusclient.conf]"

	   # Use listen-host to	limit to specific IPs or to the	IPs of a provided
	   # hostname.
	   #listen-host	= [IP|HOSTNAME]

	   # TCP and UDP port number
	   tcp-port = 4443
	   udp-port = 4443

	   # Accept connections	using a	socket file. It	accepts	HTTP
	   # connections (i.e.,	without	SSL/TLS	unlike its TCP counterpart),
	   # and uses it as the	primary	channel. That option is	experimental
	   # and it has	many known issues.
	   #  *	It can only be combined	with certificate authentication, when receiving
	   #	channel	information through proxy protocol (see	listen-proxy-proto)
	   #  *	It cannot derive any keys needed for the DTLS session (hence no	support	for dtls-psk)
	   #  *	It cannot enforce the framing of the SSL/TLS packets, and that
	   #	breaks assumptions held	by several openconnect clients.
	   # This option is not	recommended for	use, and may be	removed
	   # in	the future.
	   #listen-clear-file =	/var/run/ocserv-conn.socket

	   # The user the worker processes will	be run as. It should be
	   # unique (no	other services run as this user).
	   run-as-user = nobody
	   run-as-group	= nogroup

	   # The default server	directory. Does	not require any	devices	present.
	   #chroot-dir = /path/to/chroot

	   # socket file used for IPC with occtl. You only need	to set that,
	   # if	you use	more than a single servers.
	   #occtl-socket-file =	/var/run/occtl.socket

	   # socket file used for server IPC (worker - sec-mod), will be appended with .PID
	   # It	must be	accessible within the chroot environment (if any), so it is best
	   # specified relatively to the chroot	directory.
	   socket-file = /var/run/ocserv-socket

	   # The key and the certificates of the server
	   # The key may be a file, or any URL supported by GnuTLS (e.g.,
	   # tpmkey:uuid=xxxxxxx-xxxx-xxxx-xxxx-xxxxxxxx;storage=user
	   # or	pkcs11:object=my-vpn-key;object-type=private)
	   # The server-cert file may contain a	single certificate, or
	   # a sorted certificate chain.
	   # There may be multiple server-cert and server-key directives,
	   # but each key should correspond to the preceding certificate.
	   server-cert = /path/to/cert.pem
	   server-key =	/path/to/key.pem

	   # The server	provides following URL handlers	to obtain the certificates
	   # configured	above:
	   #  /cert.pem	  Returns the server's certificate in PEM format
	   #  /cert.der	  Returns the server's certificate in DER format
	   #  /ca.pem	  Returns the server's CA certificate in PEM format
	   #  /ca.der	  Returns the server's CA certificate in DER format

	   # Diffie-Hellman parameters.	Only needed if you require support
	   # for the DHE ciphersuites (by default this server supports ECDHE).
	   # Can be generated using:
	   # certtool --generate-dh-params --outfile /path/to/dh.pem
	   #dh-params =	/path/to/dh.pem

	   # In	case PKCS #11, TPM or encrypted	keys are used the PINs should be available
	   # in	files. The srk-pin-file	is applicable to TPM keys only,	and is the
	   # storage root key.
	   #pin-file = /path/to/pin.txt
	   #srk-pin-file = /path/to/srkpin.txt

	   # The password or PIN needed	to unlock the key in server-key	file.
	   # Only needed if the	file is	encrypted or a PKCS #11	object.	This
	   # is	an alternative method to pin-file.
	   #key-pin = 1234

	   # The SRK PIN for TPM.
	   # This is an	alternative method to srk-pin-file.
	   #srk-pin = 1234

	   # The Certificate Authority that will be used to verify
	   # client certificates (public keys) if certificate authentication
	   # is	set.
	   #ca-cert = /path/to/ca.pem

	   ### All configuration options below this line are reloaded on a SIGHUP.
	   ### The options above, will remain unchanged. Note however, that the
	   ### server-cert, server-key,	dh-params and ca-cert options will be reloaded
	   ### if the provided file changes, on	server reload. That allows certificate
	   ### rotation, but requires the server key to	remain the same	for seamless
	   ### operation. If the server	key changes on reload, there may be connection
	   ### failures	during the reloading time.

	   # Whether to	enable seccomp/Linux namespaces	worker isolation. That restricts the number of
	   # system calls allowed to a worker process, in order	to reduce damage from a
	   # bug in the	worker process.	It is available	on Linux systems at a performance cost.
	   # The performance cost is roughly 2%	overhead at transfer time (tested on a Linux 3.17.8).
	   # Note however, that	process	isolation is restricted	to the specific	libc versions
	   # the isolation was tested at. If you get random failures on	worker processes, try
	   # disabling that option and report the failures you,	along with system and debugging
	   # information at:
	   isolate-workers = true

	   # A banner to be displayed on clients
	   #banner = "Welcome"

	   # Limit the number of clients. Unset	or set to zero for unlimited.
	   #max-clients	= 1024
	   max-clients = 16

	   # Limit the number of identical clients (i.e., users	connecting
	   # multiple times). Unset or set to zero for unlimited.
	   max-same-clients = 2

	   # When the server has a dynamic DNS address (that may change),
	   # should set	that to	true to	ask the	client to resolve again	on
	   # reconnects.
	   #listen-host-is-dyndns = true

	   # When the server receives connections from a proxy,	like haproxy
	   # which supports the	proxy protocol,	set this to obtain the correct
	   # client addresses. The proxy protocol (v2) would then be expected in
	   # the TCP or	UNIX socket (not the UDP one). Although	both v1
	   # and v2 versions of	proxy protocol are supported, the v2 version
	   # is	recommended as it is more efficient in parsing.
	   #listen-proxy-proto = true

	   # Limit the number of client	connections to one every X milliseconds
	   # (X	is the provided	value).	Set to zero for	no limit.
	   #rate-limit-ms = 100

	   # Stats report time.	The number of seconds after which each
	   # worker process will report	its usage statistics (number of
	   # bytes transferred etc). This is useful when accounting like
	   # radius is in use.
	   #stats-report-time =	360

	   # Stats reset time. The period of time statistics kept by main/sec-mod
	   # processes will be reset. These are	the statistics shown by	cmd
	   # 'occtl show stats'. For daily: 86400, weekly: 604800
	   # This is unrelated to stats-report-time.
	   server-stats-reset-time = 604800

	   # Keepalive in seconds
	   keepalive = 32400

	   # Dead peer detection in seconds.
	   # Note that when the	client is behind a NAT this value
	   # needs to be short enough to prevent the NAT disassociating
	   # his UDP session from the port number. Otherwise the client
	   # could have	his UDP	connection stalled, for	several	minutes.
	   dpd = 90

	   # Dead peer detection for mobile clients. That needs	to
	   # be	higher to prevent such clients being awaken too
	   # often by the DPD messages,	and save battery.
	   # The mobile	clients	are distinguished from the header
	   # 'X-AnyConnect-Identifier-Platform'.
	   mobile-dpd =	1800

	   # If	using DTLS, and	no UDP traffic is received for this
	   # many seconds, attempt to send future traffic over the TCP
	   # connection	instead, in an attempt to wake up the client
	   # in	the case that there is a NAT and the UDP translation
	   # was deleted. If this is unset, do not attempt to use this
	   # recovery mechanism.
	   switch-to-tcp-timeout = 25

	   # MTU discovery (DPD	must be	enabled)
	   # If	set, this forces all UDP packets to carry the don't fragment
	   # (DF) bit.
	   try-mtu-discovery = false

	   # The revocation list of the	certificates issued by the 'ca-cert' above.
	   # See the manual to generate	an empty CRL initially.	The CRL	will be	reloaded
	   # periodically when ocserv detects a	change in the file. To force a reload use
	   # SIGHUP.
	   #crl	= /path/to/crl.pem

	   # If	you have a certificate from a CA that provides an OCSP
	   # service you may provide a fresh OCSP status response within
	   # the TLS handshake.	That will prevent the client from connecting
	   # independently on the OCSP server.
	   # You can update this response periodically using:
	   # ocsptool --ask --load-cert=your_cert --load-issuer=your_ca	--outfile response
	   # Make sure that you	replace	the following file in an atomic	way.
	   #ocsp-response = /path/to/ocsp.der

	   # The object	identifier that	will be	used to	read the user ID in the	client
	   # certificate. The object identifier	should be part of the certificate's DN
	   # Useful OIDs are:
	   #  CN =, UID	= 0.9.2342.19200300.100.1.1, SAN(rfc822name)
	   #cert-user-oid = 0.9.2342.19200300.100.1.1

	   # The object	identifier that	will be	used to	read the user group in the
	   # client certificate. The object identifier should be part of the certificate's
	   # DN. If the	user may belong	to multiple groups, then use multiple such fields
	   # in	the certificate's DN. Useful OIDs are:
	   #  OU (organizational unit) =
	   #cert-group-oid =

	   # Uncomment this to enable compression negotiation (LZS, LZ4).
	   #compression	= true

	   # Set the minimum size under	which a	packet will not	be compressed.
	   # That is to	allow low-latency for VoIP packets. The	default	size
	   # is	256 bytes. Modify it if	the clients typically use compression
	   # as	well of	VoIP with codecs that exceed the default value.
	   #no-compress-limit =	256

	   # GnuTLS priority string; note that SSL 3.0 is disabled by default
	   # as	there are no openconnect (and possibly anyconnect clients) using
	   # that protocol. The	string below does not enforce perfect forward
	   # secrecy, in order to be compatible	with legacy clients.
	   # Note that the most	performant ciphersuites	are the	moment are the ones
	   # involving AES-GCM.	These are very fast in x86 and x86-64 hardware,	and
	   # in	addition require no padding, thus taking full advantage	of the MTU.
	   # For that to be taken advantage of,	the openconnect	client must be
	   # used, and the server must be compiled against GnuTLS 3.2.7	or later.
	   # Use "gnutls-cli --benchmark-tls-ciphers", to see the performance
	   # difference	with AES_128_CBC_SHA1 (the default for anyconnect clients)
	   # in	your system.


	   # More combinations in priority strings are available, check
	   # E.g., the string below enforces perfect forward secrecy (PFS)
	   # on	the main channel.

	   # That option requires the established DTLS channel to use the same
	   # cipher as the primary TLS channel.	This cannot be combined	with
	   # listen-clear-file since the ciphersuite information is not	available
	   # in	that configuration. Note also, that this option	implies	that
	   # dtls-legacy option	is false; this option cannot be	enforced
	   # in	the legacy/compat protocol.
	   #match-tls-dtls-ciphers = true

	   # The time (in seconds) that	a client is allowed to stay connected prior
	   # to	authentication
	   auth-timeout	= 240

	   # The time (in seconds) that	a client is allowed to stay idle (no traffic)
	   # before being disconnected.	Unset to disable.
	   #idle-timeout = 1200

	   # The time (in seconds) that	a client is allowed to stay connected
	   # Unset to disable.
	   #session-timeout = 86400

	   # The time (in seconds) that	a mobile client	is allowed to stay idle	(no
	   # traffic) before being disconnected. Unset to disable.
	   #mobile-idle-timeout	= 2400

	   # The time (in seconds) that	a client is not	allowed	to reconnect after
	   # a failed authentication attempt.
	   min-reauth-time = 120

	   # Banning clients in	ocserv works with a point system. IP addresses
	   # that get a	score over that	configured number are banned for
	   # min-reauth-time seconds. By default a wrong password attempt is 10	points,
	   # a KKDCP POST is 1 point, and a connection is 1 point. Note	that
	   # due to difference processes being involved	the count of points
	   # will not be real-time precise.
	   # Score banning cannot be reliably used when	receiving proxied connections
	   # locally from an HTTP server (i.e.,	when listen-clear-file is used).
	   # Set to zero to disable.
	   max-ban-score = 80

	   # The time (in seconds) that	all score kept for a client is reset.
	   ban-reset-time = 1200

	   # In	case you'd like	to change the default points.
	   #ban-points-wrong-password =	10
	   #ban-points-connection = 1
	   #ban-points-kkdcp = 1

	   # Cookie timeout (in	seconds)
	   # Once a client is authenticated he's provided a cookie with
	   # which he can reconnect. That cookie will be invalidated if	not
	   # used within this timeout value. This cookie remains valid,	during
	   # the user's	connected time,	and after user disconnection it
	   # remains active for	this amount of time. That setting should allow a
	   # reasonable	amount of time for roaming between different networks.
	   cookie-timeout = 300

	   # If	this is	enabled	(not recommended) the cookies will stay
	   # valid even	after a	user manually disconnects, and until they
	   # expire. This may improve roaming with some	broken clients.
	   #persistent-cookies = true

	   # Whether roaming is	allowed, i.e., if true a cookie	is
	   # restricted	to a single IP address and cannot be re-used
	   # from a different IP.
	   deny-roaming	= false

	   # ReKey time	(in seconds)
	   # ocserv will ask the client	to refresh keys	periodically once
	   # this amount of seconds is elapsed.	Set to zero to disable (note
	   # that, some	clients	fail if	rekey is disabled).
	   rekey-time =	172800

	   # ReKey method
	   # Valid options: ssl, new-tunnel
	   #  ssl: Will	perform	an efficient rehandshake on the	channel	allowing
	   #	   a seamless connection during	rekey.
	   #  new-tunnel: Will instruct	the client to discard and re-establish the channel.
	   #	   Use this option only	if the connecting clients have issues with the ssl
	   #	   option.
	   rekey-method	= ssl

	   # Script to call when a client connects and obtains an IP.
	   # The following parameters are passed on the	environment.
	   # REASON, USERNAME, GROUPNAME, DEVICE, IP_REAL (the real IP of the client),
	   # IP_REAL_LOCAL (the	local interface	IP the client connected), IP_LOCAL
	   # (the local	IP in the P-t-P	connection), IP_REMOTE (the VPN	IP of the client),
	   # IPV6_LOCAL	(the IPv6 local	address	if there are both IPv4 and IPv6
	   # assigned),	IPV6_REMOTE (the IPv6 remote address), IPV6_PREFIX, and
	   # ID	(a unique numeric ID); REASON may be "connect" or "disconnect".
	   # In	addition the following variables OCSERV_ROUTES (the applied routes for this
	   # client), OCSERV_NO_ROUTES,	OCSERV_DNS (the	DNS servers for	this client),
	   # will contain a space separated list of routes or DNS servers. A version
	   # of	these variables	with the 4 or 6	suffix will contain only the IPv4 or
	   # IPv6 values. Only the exit	code of	the connect script is considered.
	   # An	exit code of non-zero results the user being denied access.

	   # The disconnect script will	receive	the additional values: STATS_BYTES_IN,
	   # STATS_BYTES_OUT, STATS_DURATION that contain a 64-bit counter of the bytes
	   # output from the tun device, and the duration of the session in seconds.

	   #connect-script = /usr/bin/myscript
	   #disconnect-script =	/usr/bin/myscript

	   # Script to call when the client is connected and provides a	hostname. This
	   # is	called after the connect-script, if a hostname is provided by the user,
	   # and in addition to	the previously stated variables	it provides a HOSTNAME
	   # environment variable. That	can be used with nsupdate, for example,	to
	   # register the hostname on a	DNS server. The	REASON variable	will be	"host-update".
	   # The exit code of this script is ignored.
	   #host-update-script = /usr/bin/myscript

	   # UTMP
	   # Register the connected clients to utmp. This will allow viewing
	   # the connected clients using the command 'who'.
	   #use-utmp = true

	   # Whether to	enable support for the occtl tool (i.e., either	through	D-BUS,
	   # or	via a unix socket).
	   use-occtl = true

	   # PID file. It can be overridden in the command line.
	   pid-file = /var/run/ocserv/pid

	   # Set the protocol-defined priority (SO_PRIORITY) for packets to
	   # be	sent. That is a	number from 0 to 6 with	0 being	the lowest
	   # priority. Alternatively this can be used to set the IP Type-
	   # Of-Service, by setting it to a hexadecimal	number (e.g., 0x20).
	   # This can be set per user/group or globally.
	   #net-priority = 3

	   # Set the VPN worker	process	into a specific	cgroup.	This is	Linux
	   # specific and can be set per user/group or globally.
	   #cgroup = "cpuset,cpu:test"

	   # Network settings

	   # The name to use for the tun device
	   device = vpns

	   # Whether the generated IPs will be predictable, i.e., IP stays the
	   # same for the same user when possible.
	   predictable-ips = true

	   # The default domain	to be advertised
	   default-domain =

	   # The pool of addresses that	leases will be given from. If the leases
	   # are given via Radius, or via the explicit-ip? per-user config option then
	   # these network values should contain a network with	at least a single
	   # address that will remain under the	full control of	ocserv (that is
	   # to	be able	to assign the local part of the	tun device address).
	   # Note that,	you could use addresses	from a subnet of your LAN network if you
	   # enable proxy arp in the LAN interface (see;
	   # in	that case it is	recommended to set ping-leases to true.
	   ipv4-network	=
	   ipv4-netmask	=

	   # An	alternative way	of specifying the network:
	   #ipv4-network =

	   # The IPv6 subnet that leases will be given from.
	   ipv6-network	= fda9:4efe:7e3b:03ea::/48

	   # Specify the size of the network to	provide	to clients. It is
	   # generally recommended to provide clients with a /64 network in
	   # IPv6, but any subnet may be specified. To provide clients only
	   # with a single IP use the prefix 128.
	   #ipv6-subnet-prefix = 128
	   #ipv6-subnet-prefix = 64

	   # Whether to	tunnel all DNS queries via the VPN. This is the	default
	   # when a default route is set.
	   #tunnel-all-dns = true

	   # The advertized DNS	server.	Use multiple lines for
	   # multiple servers.
	   # dns = fc00::4be0
	   dns =

	   # The NBNS server (if any)
	   #nbns =

	   # The domains over which the	provided DNS should be used. Use
	   # multiple lines for	multiple domains.
	   #split-dns =

	   # Prior to leasing any IP from the pool ping	it to verify that
	   # it	is not in use by another (unrelated to this server) host.
	   # Only set to true, if there	can be occupied	addresses in the
	   # IP	range for leases.
	   ping-leases = false

	   # Use this option to	set a link MTU value to	the incoming
	   # connections. Unset	to use the default MTU of the TUN device.
	   # Note that the MTU is negotiated using the value set and the
	   # value sent	by the peer.
	   #mtu	= 1420

	   # Unset to enable bandwidth restrictions (in	bytes/sec). The
	   # setting here is global, but can also be set per user or per group.
	   #rx-data-per-sec = 40000
	   #tx-data-per-sec = 40000

	   # The number	of packets (of MTU size) that are available in
	   # the output	buffer.	The default is low to improve latency.
	   # Setting it	higher will improve throughput.
	   #output-buffer = 10

	   # Routes to be forwarded to the client. If you need the
	   # client to forward routes to the server, you may use the
	   # config-per-user/group or even connect and disconnect scripts.
	   # To	set the	server as the default gateway for the client just
	   # comment out all routes from the server, or	use the	special	keyword
	   # 'default'.

	   route =
	   route =
	   #route = fef4:db8:1000:1001::/64
	   #route = default

	   # Subsets of	the routes above that will not be routed by
	   # the server. Note, that this may currently be not be supported
	   # by	openconnect clients.

	   no-route =

	   # Note the that following two firewalling options currently are experimental	and
	   # available in Linux	systems	with iptables software.

	   # If	set, the script	/usr/bin/ocserv-fw will	be called to restrict
	   # the user to its allowed routes and	prevent	him from accessing
	   # any other routes. In case of defaultroute,	the no-routes are restricted.
	   # All the routes applied by ocserv can be reverted using /usr/bin/ocserv-fw
	   # --removeall. This option can be set globally or in	the per-user configuration.
	   #restrict-user-to-routes = true

	   # This option implies restrict-user-to-routes set to	true. If set, the
	   # script /usr/bin/ocserv-fw will be called to restrict the user to
	   # access specific ports in the network. This	option can be set globally
	   # or	in the per-user	configuration.
	   #restrict-user-to-ports = "tcp(443),	tcp(80), udp(443), sctp(99), tcp(583), icmp(), icmpv6()"

	   # You could also use	negation, i.e.,	block the user from accessing these ports only.
	   #restrict-user-to-ports = "!(tcp(443), tcp(80))"

	   # When set to true, all client's iroutes are	made visible to	all
	   # connecting	clients	except for the ones offering them. This	option
	   # only makes	sense if config-per-user is set.
	   #expose-iroutes = true

	   # When set to true, all global routes and no-routeswill be appended to individual
	   # user or group configuration (in case you use the config-per-user
	   # or	config-per-group options. In previous versions of ocserv this
	   # was the default.
	   #append-global-routes = true

	   # Groups that a client is allowed to	select from.
	   # A client may belong in multiple groups, and in certain use-cases
	   # it	is needed to switch between them. For these cases the client can
	   # select prior to authentication. Add multiple entries for multiple groups.
	   # The group may be followed by a user-friendly name in brackets.
	   #select-group = group1
	   #select-group = group2[My special group]

	   # The name of the (virtual) group that if selected it would assign the user
	   # to	its default group.
	   #default-select-group = DEFAULT

	   # Instead of	specifying manually all	the allowed groups, you	may instruct
	   # ocserv to scan all	available groups and include the full list.
	   #auto-select-group =	true

	   # Configuration files that will be applied per user connection or
	   # per group.	Each file name on these	directories must match the username
	   # or	the groupname.
	   # The options allowed in the	configuration files are	dns, nbns,
	   #  ipv?-network, ipv4-netmask, rx/tx-per-sec, iroute, route,	no-route,
	   #  explicit-ipv4, explicit-ipv6, net-priority, deny-roaming,	no-udp,
	   #  keepalive, dpd, mobile-dpd, max-same-clients, tunnel-all-dns,
	   #  restrict-user-to-routes, user-profile, cgroup, stats-report-time,
	   #  mtu, idle-timeout, mobile-idle-timeout, restrict-user-to-ports,
	   #  hostname,	and session-timeout.
	   # Note that the 'iroute' option allows one to add routes on the server
	   # based on a	user or	group. The syntax depends on the input accepted
	   # by	the commands route-add-cmd and route-del-cmd (see below). The no-udp
	   # is	a boolean option (e.g.,	no-udp = true),	and will prevent a UDP session
	   # for that specific user or group. The hostname option will set a
	   # hostname to override any proposed by the user. Note also, that, any
	   # routes, no-routes,	DNS or NBNS servers present will overwrite the global ones.
	   # Also explicit addresses, are only allowed when they are odd. In that
	   # case the next even	address	will be	used as	the remote address (in PtP).

	   #config-per-user = /usr/local/etc/ocserv/config-per-user/
	   #config-per-group = /usr/local/etc/ocserv/config-per-group/

	   # When config-per-xxx is specified and there	is no group or user that
	   # matches, then utilize the following configuration.
	   #default-user-config	= /usr/local/etc/ocserv/defaults/user.conf
	   #default-group-config = /usr/local/etc/ocserv/defaults/group.conf

	   # The system	command	to use to setup	a route. %{R} will be replaced with the
	   # route/mask, %{RI} with the	route in CIDR format, and %{D} with the	(tun) device.
	   # The following example is from linux systems. %{R} should be something
	   # like and	%{RI} (the argument of iroute).

	   #route-add-cmd = "ip	route add %{R} dev %{D}"
	   #route-del-cmd = "ip	route delete %{R} dev %{D}"

	   # This option allows	one to forward a proxy.	The special keywords '%{U}'
	   # and '%{G}', if present will be replaced by	the username and group name.
	   #proxy-url =
	   #proxy-url ={U}/

	   # This option allows	you to specify a URL location where a client can
	   # post using	MS-KKDCP, and the message will be forwarded to the provided
	   # KDC server. That is a translation URL between HTTP	and Kerberos.
	   # You can have the same path	used for multiple realms. To authenticate
	   # in	client side, in	MIT kerberos you'll need to add	in krb5.conf:
	   #   EXAMPLE.COM = {
	   #	 kdc =
	   #	 http_anchors =	FILE:/etc/ocserv-ca.pem
	   #   }
	   # In	some distributions the krb5-k5tls plugin of kinit is required.
	   # The following option is available in ocserv, when compiled	with GSSAPI support.

	   #kkdcp = "/KdcProxy KERBEROS.REALM udp@"
	   #kkdcp = "/KdcProxy KERBEROS.REALM tcp@"
	   #kkdcp = "/KdcProxy KERBEROS.REALM tcp@[::1]:88"

	   # Client profile xml. This can be used to advertise alternative servers
	   # to	the client. A minimal file can be:
	   # <?xml version="1.0" encoding="UTF-8"?>
	   # <AnyConnectProfile	xmlns="" xmlns:xsi="" xsi:schemaLocation=" AnyConnectProfile.xsd">
	   #	<ServerList>
	   #	     <HostEntry>
	   #		    <HostName>VPN Server name</HostName>
	   #		    <HostAddress>localhost</HostAddress>
	   #	     </HostEntry>
	   #	</ServerList>
	   # </AnyConnectProfile>
	   # Other fields may be used by some of the CISCO clients.
	   # This file must be accessible from inside the worker's chroot.
	   # Note that enabling	this option is not recommended as it will allow
	   # the worker	processes to open arbitrary files (when	isolate-workers	is
	   # set to true).
	   #user-profile = profile.xml

	   # The following options are for (experimental) AnyConnect client
	   # compatibility.

	   # This option will enable the pre-draft-DTLS	version	of DTLS, and
	   # will not require clients to present their certificate on every TLS
	   # connection. It must be set	to true	to support legacy CISCO	clients
	   # and openconnect clients < 7.08. When set to true, it implies dtls-legacy =	true.
	   cisco-client-compat = true

	   # This option allows	one to disable the DTLS-PSK negotiation	(enabled by default).
	   # The DTLS-PSK negotiation was introduced in	ocserv 0.11.5 to deprecate
	   # the pre-draft-DTLS	negotiation inherited from AnyConnect. It allows the
	   # DTLS channel to negotiate its ciphers and the DTLS	protocol version.
	   #dtls-psk = false

	   # This option allows	one to disable the legacy DTLS negotiation (enabled by default,
	   # but that may change in the	future).
	   # The legacy	DTLS uses a pre-draft version of the DTLS protocol and was
	   # from AnyConnect protocol. It has several limitations, that	are addressed
	   # by	the dtls-psk protocol supported	by openconnect 7.08+.
	   dtls-legacy = true

	   #Advanced options

	   # Option to allow sending arbitrary custom headers to the client after
	   # authentication and	prior to VPN tunnel establishment. You shouldn't
	   # need to use this option normally; if you do and you think that
	   # this may help others, please send your settings and reason	to
	   # the openconnect mailing list. The special keywords	'%{U}'
	   # and '%{G}', if present will be replaced by	the username and group name.
	   #custom-header = "X-My-Header: hi there"

       One of the following exit values	will be	returned:

       0 " (EXIT_SUCCESS)"
	      Successful program execution.

       1 " (EXIT_FAILURE)"
	      The operation failed or the command syntax was not valid.

       70 " (EX_SOFTWARE)"
	      libopts had an internal operational error.  Please report	it to  Thank you.

       The server has been tested to be	compatible with	the openconnect	VPN
       client. However,	it is also known to be compatible with certain CISCO
       AnyConnect clients.  To enable compatibility with CISCO's AnyConnect
       the cisco-client-compat and user-profile	options	must be	set in oc-
       serv's configuration.

       ocpasswd(8), occtl(8)

       Nikos Mavrogiannopoulos and others

       Copyright (C) 2013-2017 Nikos Mavrogiannopoulos all rights reserved.
       This program is released	under the terms	of the GNU General Public Li-
       cense, version 2.

       Please send bug reports to:

       This manual page	was AutoGen-erated from	the ocserv option definitions.

0.11.8				  08 Jul 2017			     ocserv(8)


Want to link to this manual page? Use this URL:

home | help