Provided by: openconnect_9.12-1build5_amd64 
NAME
openconnect - Multi-protocol VPN client, for Cisco AnyConnect VPNs and others
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]
[--compression MODE] [-d,--deflate] [-D,--no-deflate] [--force-dpd interval]
[--force-trojan interval] [-F,--form-entry form:opt=value] [-g,--usergroup group] [-h,--help]
[--http-auth methods] [--external-browser browser] [-i,--interface ifname] [-l,--syslog]
[--timestamp] [--passtos] [-U,--setuid user] [--csd-user user] [-m,--mtu mtu]
[--base-mtu mtu] [-p,--key-password pass] [-P,--proxy proxyurl] [--proxy-auth methods]
[--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] [--dtls12-ciphers list]
[--dtls-local-port port] [--dump-http-traffic] [--no-system-trust] [--pfs] [--no-dtls]
[--no-http-keepalive] [--no-passwd] [--no-xmlpost] [--non-inter] [--passwd-on-stdin]
[--protocol proto] [--token-mode mode] [--token-secret {secret[,counter]|@file}]
[--reconnect-timeout seconds] [--resolve host:ip] [--sni host] [--servercert sha1]
[--useragent string] [--version-string string] [--local-hostname string] [--os string]
[--server] [https://]host[:port][/group]
DESCRIPTION
The program openconnect connects to VPN servers which use standard TLS/SSL, DTLS, and ESP protocols for
data transport.
It was originally written to support Cisco "AnyConnect" VPN servers, and has since been extended with
experimental support for Juniper Network Connect (--protocol=nc), Junos/Ivanti Pulse VPN servers
(--protocol=pulse), PAN GlobalProtect VPN servers (--protocol=gp), F5 Big-IP VPN servers (--protocol=f5),
Fortinet Fortigate VPN servers (--protocol=fortinet), and Array Networks SSL VPN servers
(--protocol=array).
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 authentication cookie which can be used to make the real VPN connection.
The second phase uses that cookie to connect to a tunnel via HTTPS, and data packets can be passed over
the resulting connection. When possible, a UDP tunnel is also configured: AnyConnect uses DTLS, while
Juniper and GlobalProtect use UDP-encapsulated ESP. The UDP tunnel may be disabled with --no-dtls, but is
preferred when correctly supported by the server and network for performance reasons. (TCP performs
poorly and unreliably over TCP-based tunnels; see http://sites.inka.de/~W1011/devel/tcp-tcp.html.)
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 [,--mca-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.
The --mca-certificate option sets the secondary certificate for multi-certificate authentication
(according to Cisco's terminology, the SSL client certificate is called the "machine" certificate,
and the second certificate is called the "user" certificate).
-e,--cert-expire-warning=DAYS
Give a warning when SSL client certificate has DAYS left before expiry
-k,--sslkey=KEY [,--mca-key=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.
The --mca-key option sets the private key for the secondary certificate (see --mca-certificate).
-C,--cookie=COOKIE
Use authentication cookie COOKIE.
--cookie-on-stdin
Read cookie from standard input.
-d,--deflate
Enable all compression, including stateful modes. By default, only stateless compression
algorithms are enabled.
-D,--no-deflate
Disable all compression.
--compression=MODE
Set compression mode, where MODE is one of stateless, none, or all.
By default, only stateless compression algorithms which do not maintain state from one packet to
the next (and which can be used on UDP transports) are enabled. By setting the mode to all
stateful algorithms (currently only zlib deflate) can be enabled. Or all compression can be
disabled by setting the mode to none.
--force-dpd=INTERVAL
Use INTERVAL as Dead Peer Detection interval (in seconds). This will cause the client to use DPD
at the specified interval even if the server hasn't requested it, or at a different interval from
the one requested by the server.
DPD mechanisms vary by protocol and by transport (TLS or DTLS/ESP), but are all functionally
similar: they enable either the VPN client or the VPN server to transmit a signal to the peer,
requesting an immediate reply which can be used to confirm that the link between the two peers is
still working.
-g,--usergroup=GROUP
Set the URL path of the initial HTTPS connection to the server.
With some protocols, this path may function as a login group or realm, hence the naming of this
option. For example, the following invocations of OpenConnect are equivalent:
openconnect --usergroup=loginPath vpn.server.com
openconnect https://vpn.server.com/loginPath
-F,--form-entry=FORM:OPTION[=VALUE]
Provide authentication form input, where FORM and OPTION are the identifiers from the form and the
specific input field, and VALUE is the string to be filled in automatically. For example, the
standard username field (also handled by the --user option) could also be provided with this
option thus: --form-entry main:username=joebloggs.
If VALUE is not specified, this option will cause a hidden form field to be treated as a standard
text-input field.
This option should not be used to enter passwords. --passwd-on-stdin should be used for that
purpose. Not only will this option expose the password value via the OpenConnect process's command
line, but unlike --passwd-on-stdin this option will not recognize the case of an incorrect
password, and stop trying to re-enter it repeatedly.
-h,--help
Display help text
--http-auth=METHODS
Use only the specified methods for HTTP authentication to a server. By default, only Negotiate,
NTLM and Digest authentication are enabled. Basic authentication is also supported but because it
is insecure it must be explicitly enabled. The argument is a comma-separated list of methods to be
enabled. Note that the order does not matter: OpenConnect will use Negotiate, NTLM, Digest and
Basic authentication in that order, if each is enabled, regardless of the order specified in the
METHODS string.
--external-browser=BROWSER
Set BROWSER as the executable used by OpenConnect to handle the authentication process with
gateways that support the single-sign-on-external-browser authentication method.
-i,--interface=IFNAME
Use IFNAME for tunnel interface
-l,--syslog
After tunnel is brought up, use syslog for further progress messages
--timestamp
Prepend a timestamp to each progress message
--passtos
Copy TOS / TCLASS of payload packet into DTLS and ESP packets. This is not set by default because
it may leak information about the payload (for example, by differentiating voice/video traffic).
-U,--setuid=USER
Drop privileges after connecting, to become user USER
--csd-user=USER
Drop privileges during execution of trojan binary or script (CSD, TNCC, or HIP).
--csd-wrapper=SCRIPT
Run SCRIPT instead of the trojan binary or script.
--force-trojan=INTERVAL
Use INTERVAL as interval (in seconds) for repeat execution of Trojan binary or script, overriding
default and/or server-set interval.
-m,--mtu=MTU
Request MTU from server as the MTU of the tunnel.
--base-mtu=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 [,--mca-key-password=PASS]
Provide passphrase for certificate file, or SRK (System Root Key) PIN for TPM
--mca-key-password provides the passphrase for the secondary certificate (see --mca-certificate).
-P,--proxy=PROXYURL
Use HTTP or SOCKS proxy for connection. A username and password can be provided in the given URL,
and will be used for authentication. If authentication is required but no credentials are given,
GSSAPI and automatic NTLM authentication using Samba's ntlm_auth helper tool may be attempted.
--proxy-auth=METHODS
Use only the specified methods for HTTP authentication to a proxy. By default, only Negotiate,
NTLM and Digest authentication are enabled. Basic authentication is also supported but because it
is insecure it must be explicitly enabled. The argument is a comma-separated list of methods to be
enabled. Note that the order does not matter: OpenConnect will use Negotiate, NTLM, Digest and
Basic authentication in that order, if each is enabled, regardless of the order specified in the
METHODS string.
--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 packets. The default is 32. A high value may allow better overall
bandwidth but at a cost of latency. If you run Voice over IP or other interactive traffic over the
VPN, you don't want those packets to be queued behind thousands of other large packets which are
part of a bulk transfer.
This option sets the maximum inbound and outbound packet queue sizes in OpenConnect itself, which
control how many packets will be sent and received in a single batch, as well as affecting other
buffering such as the socket send buffer (SO_SNDBUF) for network connections and the OS tunnel
device.
Ultimately, the right size for a queue is "just enough packets that it never quite gets empty
before more are pushed to it". Any higher than that is simply introducing bufferbloat and
additional latency with no benefit. With the default of 32, we are able to saturate a single
Gigabit Ethernet from modest hardware, which is more than enough for most VPN users.
If OpenConnect is built with vhost-net support, it will only be used if the queue length is set to
16 or more. This is because vhost-net introduces a small amount of additional latency, but
improves total bandwidth quite considerably for those operating at high traffic rates. Thus it
makes sense to use it when the user has indicated a preference for bandwidth over latency, by
increasing the queue size.
-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 https://www.infradead.org/openconnect/vpnc-script.html
for more information. This version of OpenConnect is configured to use /usr/share/vpnc-
scripts/vpnc-script by default.
On Windows, a relative directory for the default script will be handled as starting from the
directory that the openconnect executable is running from, rather than the current directory. The
script will be invoked with the command-based script host cscript.exe.
-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.
--server=[https://]HOST[:PORT][/PATH]
Define the VPN server as a simple HOST or as an URL containing the HOST and optionally the PORT
number and the PATH; with some protocols, the path may function as a login group or realm, and it
may equivalently be specified with --usergroup.
As an alternative, define the VPN server as non-option command line argument.
-u,--user=NAME
Set login username to NAME
-V,--version
Report version number
-v,--verbose
More output (may be specified multiple times for additional output)
-x,--xmlconfig=CONFIG
XML config file
--authgroup=GROUP
Select GROUP from authentication dropdown or list entry.
Many VPNs require a selection from a dropdown or list during the authentication process. This
selection may be known as authgroup (on Cisco VPNs), realm (Juniper, Pulse, Fortinet), domain
(F5), and gateway (GlobalProtect). This option attempts to automatically fill the appropriate
protocol-specific field with the desired value.
--authenticate
Authenticate to the VPN, output the information needed to make the connection in a form which can
be used to set shell environment variables, and then exit.
When invoked with this option, OpenConnect will not actually create the VPN connection or
configure a tunnel interface, but if successful will print something like the following to stdout:
COOKIE='3311180634@13561856@1339425499@B315A0E29D16C6FD92EE...'
HOST='10.0.0.1'
CONNECT_URL='https://vpnserver.example.com'
FINGERPRINT='469bb424ec8835944d30bc77c77e8fc1d8e23a42'
RESOLVE='vpnserver.example.com:10.0.0.1'
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 $CONNECT_URL --servercert $FINGERPRINT --resolve $RESOLVE
Earlier versions of OpenConnect produced only the HOST variable (containing the numeric server
address), and not the CONNECT_URL or RESOLVE variables. Subsequently, we discovered that servers
behind proxies may not respond correctly unless the correct DNS name is present in the connection
phase, and we added support for VPN protocols where the server URL's path component may be
significant in the connection phase, prompting the addition of CONNECT_URL and RESOLVE, and the
recommendation to use them as described above. If you are not certain that you are invoking a
newer version of OpenConnect which outputs these variables, use the following command-line
(compatible with most Bourne shell derivatives) which will work with either a newer or older
version:
sudo openconnect --cookie-on-stdin ${CONNECT_URL:-$HOST} --servercert $FINGERPRINT ${RESOLVE:+--resolve=$RESOLVE}
--cookieonly
Fetch and print cookie only; don't connect (this is essentially a subset of --authenticate).
--printcookie
Print cookie to stdout before connecting (see --authenticate for the meaning of this cookie)
--cafile=FILE
Additional CA file for server verification. By default, this simply causes OpenConnect to trust
additional root CA certificate(s) in addition to those trusted by the system. Use
--no-system-trust to prevent OpenConnect from trusting the system default certificate authorities.
--no-system-trust
Do not trust the system default certificate authorities. If this option is given, only certificate
authorities given with the --cafile option, if any, will be trusted automatically.
--disable-ipv6
Do not advertise IPv6 capability to server
--dtls-ciphers=LIST
Set OpenSSL ciphers to support for DTLS
--dtls12-ciphers=LIST
Set OpenSSL ciphers for Cisco's DTLS v1.2
--dtls-local-port=PORT
Use PORT as the local port for DTLS and UDP datagrams
--dump-http-traffic
Enable verbose output of all HTTP requests and the bodies of all responses received from the
server.
--pfs Enforces Perfect Forward Secrecy (PFS). That ensures that if the server's long-term key is
compromised, any session keys established before the compromise will be unaffected. If this option
is provided and the server does not support PFS in the TLS channel the connection will fail.
PFS is available in Cisco ASA releases 9.1(2) and higher; a suitable cipher suite may need to be
manually enabled by the administrator using the ssl encryption setting.
--no-dtls
Disable DTLS and ESP
--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 recognizing 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-external-auth
Prevent OpenConnect from advertising to the server that it supports any kind of authentication
mode that requires an external browser.
Some servers will force the client to use such an authentication mode if the client advertises it,
but fallback to a more "scriptable" authentication mode if the client doesn't appear to support
it.
--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 https://www.infradead.org/openconnect/mail.html and report this to
the developers.
--allow-insecure-crypto
The ancient, broken 3DES and RC4 ciphers are insecure; we explicitly disable them by default.
However, some still-in-use VPN servers can't do any better.
This option enables use of these insecure ciphers, as well as the use of SHA1 for server
certificate validation.
--non-inter
Do not expect user input; exit if it is required.
--passwd-on-stdin
Read password from standard input
--protocol=PROTO
Select VPN protocol PROTO to be used for the connection. Supported protocols are anyconnect for
Cisco AnyConnect (the default), nc for experimental support for Juniper Network Connect (also
supported by most Junos/Ivanti Pulse servers), pulse for experimental support for Junos/Ivanti
Pulse, gp for experimental support for PAN GlobalProtect, f5 for experimental support for F5 Big-
IP, fortinet for experimental support for Fortinet Fortigate, and array for experimental support
for Array Networks SSL VPN.
See https://www.infradead.org/openconnect/protocols.html for details on features and deficiencies
of the individual protocols.
OpenConnect does not yet support all of the authentication options used by Pulse, nor does it
support Host Checker/TNCC with Pulse. If your Junos/Ivanti Pulse VPN is not yet supported with
--protocol=pulse, then --protocol=nc may be a useful fallback option.
--token-mode=MODE
Enable one-time password generation using the MODE algorithm. --token-mode=rsa will call
libstoken to generate an RSA SecurID tokencode, --token-mode=totp will generate an RFC 6238 time-
based password, and --token-mode=hotp will generate an RFC 4226 HMAC-based password. Yubikey
tokens which generate OATH codes in hardware are supported with --token-mode=yubioath.
--token-mode=oidc will use the provided OpenIDConnect token as an RFC 6750 bearer token.
--token-secret={ SECRET[,COUNTER] | @FILENAME }
The secret to use when generating one-time passwords/verification codes. Base 32-encoded
TOTP/HOTP secrets can be used by specifying "base32:" at the beginning of the secret, and for HOTP
secrets the token counter can be specified following a comma.
RSA SecurID secrets can be specified as an Android/iPhone URI or a raw numeric CTF string (with or
without dashes).
For Yubikey OATH the token secret specifies the name of the credential to be used. If not
provided, the first OATH credential found on the device will be used.
For OIDC the secret is the bearer token to be used.
FILENAME, if specified, can contain any of the above strings. Or, it can contain a SecurID XML
(SDTID) seed.
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=SECONDS
After disconnection or Dead Peer Detection, keep trying to reconnect for SECONDS. The default is
300 seconds, which means that openconnect can recover a VPN connection after a temporary network
outage lasting up to 300 seconds.
--resolve=HOST:IP
Automatically resolve the hostname HOST to IP instead of using the normal resolver to look it up.
--sni=HOST
When creating new TLS connections, always present the hostname HOST as the SNI (Server Name
Indication) in place of the correct hostname, which will still be sent in the HTTP 'Host:' header,
and expect the peer's certificate to match the SNI rather than the correct hostname. This may be
useful for Domain Fronting, by which some filtered or censored Internet connections can be
bypassed.
Note that sending different values for the SNI and 'Host:' header violates HTTP standards and is
prevented by many cloud hosting providers.
--servercert=HASH
Accept server's SSL certificate only if it matches the provided fingerprint. This option implies
--no-system-trust, and may be specified multiple times in order to accept multiple possible
fingerprints.
The allowed fingerprint types are SHA1, SHA256, and PIN-SHA256. They are distinguished by the
'sha1:', 'sha256:' and 'pin-sha256:' prefixes to the encoded hash. The first two are custom
identifiers providing hex encoding of the peer's public key, while 'pin-sha256:' is the RFC7469
key PIN, which utilizes base64 encoding. To ease certain testing use-cases, a partial match of the
hash will also be accepted, if it is at least 4 characters past the prefix.
--useragent=STRING
Use STRING as 'User-Agent:' field value in HTTP header.
Some VPN servers may require specific values matching those sent by proprietary VPN clients in
order to successfully authenticate or connect. For example, when connecting to a Cisco VPN server,
--useragent 'AnyConnect Windows 4.10.06079' or --useragent 'Cisco AnyConnect VPN Agent for Windows
2.2.0133', or when connecting to a Pulse server, --useragent 'Pulse-Secure/9.1.11.6725'.
--version-string=STRING
Use STRING as the software version reported to the head end. (e.g. --version-string '2.2.0133')
--local-hostname=STRING
Use STRING as 'X-CSTP-Hostname:' field value in HTTP header. For example --local-hostname 'mypc',
will advertise the value 'mypc' as the suggested hostname to point to the provided IP address.
--os=STRING
OS type to report to gateway. Recognized values are: linux, linux-64, win, mac-intel, android,
apple-ios. Reporting a different OS type may affect the dynamic access policy (DAP) applied to
the VPN session. If the gateway requires CSD, it will also cause the corresponding CSD trojan
binary to be downloaded, so you may need to use --csd-wrapper if this code is not executable on
the local machine.
SIGNALS
In the data phase of the connection, the following signals are handled:
SIGINT / SIGTERM
performs a clean shutdown by logging the session off, disconnecting from the gateway, and running
the vpnc-script to restore the network configuration.
SIGHUP disconnects from the gateway and runs the vpnc-script, but does not log the session off; this
allows for reconnection later using --cookie.
SIGUSR1
writes progress message with detailed connection information and statistics.
SIGUSR2
forces an immediate disconnection and reconnection; this can be used to quickly recover from LAN
IP address changes.
LIMITATIONS
See https://www.infradead.org/openconnect/contribute.html for various features that we wish OpenConnect
had, and https://www.infradead.org/openconnect/protocols.html for information on the quirks and
limitations of the individual VPN protocols.
SEE ALSO
ocserv(8)
AUTHORS
David Woodhouse <dwmw2@infradead.org>
OPENCONNECT(8)