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OpenConnect VPN client

Building vpnc-script Connecting Manual

# OPENCONNECT

NAME
SYNOPSIS
DESCRIPTION
OPTIONS
LIMITATIONS
AUTHORS

## NAME

openconnect − Connect to Cisco AnyConnect VPN

## SYNOPSIS

| openconnect |  | [−−config configfile] [−b,−−background] [−−pid−file pidfile] [−c,−−certificate cert] [−e,−−cert−expire−warning days] [−k,−−sslkey key] [−C,−−cookie cookie] [−−cookie−on−stdin] [−d,−−deflate] [−D,−−no−deflate] [−−force−dpd interval] [−g,−−usergroup group] [−h,−−help] [−i,−−interface ifname] [−l,−−syslog] [−U,−−setuid user] [−−csd−user user] [−m,−−mtu mtu] [−−basemtu mtu] [−p,−−key−password pass] [−P,−−proxy proxyurl] [−−no−proxy] [−−libproxy] [−−key−password−from−fsid] [−q,−−quiet] [−Q,−−queue−len len] [−s,−−script vpnc−script] [−S,−−script−tun] [−u,−−user name] [−V,−−version] [−v,−−verbose] [−x,−−xmlconfig config] [−−authgroup group] [−−authenticate] [−−cookieonly] [−−printcookie] [−−cafile file] [−−disable−ipv6] [−−dtls−ciphers list] [−−dtls−local−port port] [−−dump−http−traffic] [−−no−cert−check] [−−no−dtls] [−−no−http−keepalive] [−−no−passwd] [−−no−xmlpost] [−−non−inter] [−−passwd−on−stdin] [−−token-mode mode] [−−token-secret secret] [−−reconnect−timeout] [−−servercert sha1] [−−useragent string] [−−os string] [https://]server[:port][/group]

## DESCRIPTION

The program openconnect connects to Cisco "AnyConnect" VPN servers, which use standard TLS and DTLS protocols for data transport.

The connection happens in two phases. First there is a simple HTTPS connection over which the user authenticates somehow − by using a certificate, or password or SecurID, etc. Having authenticated, the user is rewarded with an HTTP cookie which can be used to make the real VPN connection.

The second phase uses that cookie in an HTTPS CONNECT request, and data packets can be passed over the resulting connection. In auxiliary headers exchanged with the CONNECT request, a Session−ID and Master Secret for a DTLS connection are also exchanged, which allows data transport over UDP to occur.

## OPTIONS

−−config=CONFIGFILE

Read further options from CONFIGFILE before continuing to process options from the command line. The file should contain long-format options as would be accepted on the command line, but without the two leading −− dashes. Empty lines, or lines where the first non-space character is a # character, are ignored.

Any option except the config option may be specified in the file.

−b,−−background

Continue in background after startup

−−pid−file=PIDFILE

Save the pid to PIDFILE when backgrounding

−c,−−certificate=CERT

Use SSL client certificate CERT which may be either a file name or, if OpenConnect has been built with an appropriate version of GnuTLS, a PKCS#11 URL.

−e,−−cert−expire−warning=DAYS

Give a warning when SSL client certificate has DAYS left before expiry

−k,−−sslkey=KEY

Use SSL private key KEY which may be either a file name or, if OpenConnect has been built with an appropriate version of GnuTLS, a PKCS#11 URL.

−C,−−cookie=COOKIE

Use WebVPN cookie COOKIE

−−cookie−on−stdin

Read cookie from standard input

−d,−−deflate

Enable compression (default)

−D,−−no−deflate

Disable compression

−−force−dpd=INTERVAL

Use INTERVAL as minimum Dead Peer Detection interval for CSTP and DTLS, forcing use of DPD even when the server doesn’t request it.

−g,−−usergroup=GROUP

Use GROUP as login UserGroup

−h,−−help

Display help text

−i,−−interface=IFNAME

Use IFNAME for tunnel interface

−l,−−syslog

Use syslog for progress messages

−U,−−setuid=USER

Drop privileges after connecting, to become user USER

−−csd−user=USER

Drop privileges during CSD (Cisco Secure Desktop) script execution.

−−csd−wrapper=SCRIPT

Run SCRIPT instead of the CSD (Cisco Secure Desktop) script.

−m,−−mtu=MTU

Request MTU from server as the MTU of the tunnel.

−−basemtu=MTU

Indicate MTU as the path MTU between client and server on the unencrypted network. Newer servers will automatically calculate the MTU to be used on the tunnel from this value.

−p,−−key−password=PASS

Provide passphrase for certificate file, or SRK (System Root Key) PIN for TPM

−P,−−proxy=PROXYURL

Use HTTP or SOCKS proxy for connection

−−no−proxy

Disable use of proxy

−−libproxy

Use libproxy to configure proxy automatically (when built with libproxy support)

−−key−password−from−fsid

Passphrase for certificate file is automatically generated from the fsid of the file system on which it is stored. The fsid is obtained from the statvfs(2) or statfs(2) system call, depending on the operating system. On a Linux or similar system with GNU coreutils, the fsid used by this option should be equal to the output of the command:

    stat −−file−system −−printf=%i\\n $CERTIFICATE

It is not the same as the 128−bit UUID of the file system.

−q,−−quiet

Less output

−Q,−−queue−len=LEN

Set packet queue limit to LEN pkts

−s,−−script=SCRIPT

Invoke SCRIPT to configure the network after connection. Without this, routing and name service are unlikely to work correctly. The script is expected to be compatible with the vpnc−script which is shipped with the "vpnc" VPN client. See http://www.infradead.org/openconnect/vpnc-script.html for more information. This version of OpenConnect is configured to use /etc/vpnc/vpnc-script by default.

−S,−−script−tun

Pass traffic to ’script’ program over a UNIX socket, instead of to a kernel tun/tap device. This allows the VPN IP traffic to be handled entirely in userspace, for example by a program which uses lwIP to provide SOCKS access into the VPN.

−u,−−user=NAME

Set login username to NAME

−V,−−version

Report version number

−v,−−verbose

More output

−x,−−xmlconfig=CONFIG

XML config file

−−authgroup=GROUP

Choose authentication login selection

−−authenticate

Authenticate only, and output the information needed to make the connection a form which can be used to set shell environment variables. When invoked with this option, openconnect will not make the connection, but if successful will output something like the following to stdout:
COOKIE=3311180634@13561856@1339425499@B315A0E29D16C6FD92EE...
HOST=10.0.0.1
FINGERPRINT=469bb424ec8835944d30bc77c77e8fc1d8e23a42
Thus, you can invoke openconnect as a non-privileged user (with access to the user’s PKCS#11 tokens, etc.) for authentication, and then invoke openconnect separately to make the actual connection as root:
eval ‘openconnect --authenticate https://vpnserver.example.com‘;
[ -n $COOKIE ] && echo $COOKIE |
sudo openconnect --cookie-on-stdin $HOST --servercert $FINGERPRINT

−−cookieonly

Fetch webvpn cookie only; don’t connect

−−printcookie

Print webvpn cookie before connecting

−−cafile=FILE

Cert file for server verification

−−disable−ipv6

Do not advertise IPv6 capability to server

−−dtls−ciphers=LIST

Set OpenSSL ciphers to support for DTLS

−−dtls−local−port=PORT

Use PORT as the local port for DTLS datagrams

−−dump−http−traffic

Enable verbose output of all HTTP requests and the bodies of all responses received from the server.

−−no−cert−check

Do not require server SSL certificate to be valid. Checks will still happen and failures will cause a warning message, but the connection will continue anyway. You should not need to use this option − if your servers have SSL certificates which are not signed by a trusted Certificate Authority, you can still add them (or your private CA) to a local file and use that file with the −−cafile option.

−−no−dtls

Disable DTLS

−−no−http−keepalive

Version 8.2.2.5 of the Cisco ASA software has a bug where it will forget the client’s SSL certificate when HTTP connections are being re−used for multiple requests. So far, this has only been seen on the initial connection, where the server gives an HTTP/1.0 redirect response with an explicit Connection: Keep−Alive directive. OpenConnect as of v2.22 has an unconditional workaround for this, which is never to obey that directive after an HTTP/1.0 response.

However, Cisco’s support team has failed to give any competent response to the bug report and we don’t know under what other circumstances their bug might manifest itself. So this option exists to disable ALL re−use of HTTP sessions and cause a new connection to be made for each request. If your server seems not to be recognising your certificate, try this option. If it makes a difference, please report this information to the openconnect−devel@lists.infradead.org mailing list.

−−no−passwd

Never attempt password (or SecurID) authentication.

−−no−xmlpost

Do not attempt to post an XML authentication/configuration request to the server; use the old style GET method which was used by older clients and servers instead.

This option is a temporary safety net, to work around potential compatibility issues with the code which falls back to the old method automatically. It causes OpenConnect to behave more like older versions (4.08 and below) did. If you find that you need to use this option, then you have found a bug in OpenConnect. Please see http://www.infradead.org/openconnect/mail.html and report this to the developers.

−−non−inter

Do not expect user input; exit if it is required.

−−passwd−on−stdin

Read password from standard input

−−token−mode=MODE

Enable one-time password generation using the MODE algorithm. −−token−mode=rsa will call libstoken to generate an RSA SecurID tokencode, and −−token−mode=totp will call liboath to generate an RFC 6238 password.

−−token−secret=SECRET

The secret to use when generating one-time passwords/verification codes. Base 32-encoded TOTP secrets can be used by specifying "base32:" at the beginning of the secret. If this option is omitted, and −−token−mode is "rsa", libstoken will try to use the software token seed saved in ~/.stokenrc by the "stoken import" command.

−−reconnect−timeout

Keep reconnect attempts until so much seconds are elapsed. The default timeout is 300 seconds, which means that openconnect can recover VPN connection after a temporary network down time of 300 seconds.

−−servercert=SHA1

Accept server’s SSL certificate only if its fingerprint matches SHA1.

−−useragent=STRING

Use STRING as ’User−Agent:’ field value in HTTP header. (e.g. −−useragent ’Cisco AnyConnect VPN Agent for Windows 2.2.0133’)

−−os=STRING

OS type to report to gateway. Recognized values are: linux, linux-64, mac, win. Reporting a different OS type may affect the security policy applied to the VPN session.

## LIMITATIONS

Note that although IPv6 has been tested on all platforms on which openconnect is known to run, it depends on a suitable vpnc−script to configure the network. The standard vpnc−script shipped with vpnc 0.5.3 is not capable of setting up IPv6 routes; the one from git://git.infradead.org/users/dwmw2/vpnc−scripts.git will be required.

## AUTHORS

David Woodhouse <dwmw2@infradead.org>