Provided by: vpnc_0.5.3+git20220927-1build2_amd64 
NAME
vpnc - client for Cisco VPN3000 Concentrator, IOS and PIX
SYNOPSIS
vpnc [--version] [--print-config] [--help] [--long-help] [options] [config files]
DESCRIPTION
This manual page documents briefly the vpnc and vpnc-disconnect commands.
vpnc is a VPN client for the Cisco 3000 VPN Concentrator, creating a IPSec-like
connection as a tunneling network device for the local system. It uses the TUN/TAP driver
in Linux kernel 2.4 and above and device tun(4) on BSD. The created connection is
presented as a tunneling network device to the local system.
OBLIGATORY WARNING: the most used configuration (XAUTH authentication with pre-shared keys
and password authentication) is insecure by design, be aware of this fact when you use
vpnc to exchange sensitive data like passwords!
The vpnc daemon by itself does not set any routes, but it calls vpnc-script to do this
job. vpnc-script displays a connect banner. If the concentrator supplies a network list
for split-tunneling these networks are added to the routing table. Otherwise the default-
route will be modified to point to the tunnel. Further a host route to the concentrator
is added in the later case. If the client host needs DHCP, care must be taken to add
another host route to the DHCP-Server around the tunnel.
The vpnc-disconnect command is used to terminate the connection previously created by vpnc
and restore the previous routing configuration.
CONFIGURATION
The daemon reads configuration data from the following places:
• command line options
• config file(s) specified on the command line
• /etc/vpnc/default.conf
• /etc/vpnc.conf
• prompting the user if not found above
vpnc can parse options and configuration files in any order. However the first place to
set an option wins. configuration filenames which do not contain a / will be searched at
/etc/vpnc/<filename> and /etc/vpnc/<filename>.conf. Otherwise <filename> and
<filename>.conf will be used. If no configuration file is specified on the command-line
at all, both /etc/vpnc/default.conf and /etc/vpnc.conf will be loaded.
Additionally, if the configuration file "-" is specified on the command-line vpnc will
read configuration from stdin. The configuration is parsed and the connection proceeds
when stdin is closed or the special character CEOT (CTRL-D) is read.
OPTIONS
The program options can be either given as arguments (but not all of them for security
reasons) or be stored in a configuration file.
--gateway <ip/hostname>
IP/name of your IPSec gateway
conf-variable: IPSec gateway <ip/hostname>
--id <ASCII string>
your group name
conf-variable: IPSec ID <ASCII string>
--secret <ASCII string>
your group password (cleartext)
conf-variable: IPSec secret <ASCII string>
(configfile only option)
your group password (obfuscated)
conf-variable: IPSec obfuscated secret <hex string>
--username <ASCII string>
your username
conf-variable: Xauth username <ASCII string>
--password <ASCII string>
your password (cleartext)
conf-variable: Xauth password <ASCII string>
(configfile only option)
your password (obfuscated)
conf-variable: Xauth obfuscated password <hex string>
--domain <ASCII string>
(NT-) Domain name for authentication
conf-variable: Domain <ASCII string>
--xauth-inter
enable interactive extended authentication (for challenge response auth)
conf-variable: Xauth interactive
--vendor <cisco/netscreen/fortigate>
vendor of your IPSec gateway
Default: cisco
conf-variable: Vendor <cisco/netscreen/fortigate>
--natt-mode <natt/none/force-natt/cisco-udp>
Which NAT-Traversal Method to use:
• natt -- NAT-T as defined in RFC3947
• none -- disable use of any NAT-T method
• force-natt -- always use NAT-T encapsulation even without presence of a NAT
device (useful if the OS captures all ESP traffic)
• cisco-udp -- Cisco proprietary UDP encapsulation, commonly over Port 10000
Note: cisco-tcp encapsulation is not yet supported
Default: natt
conf-variable: NAT Traversal Mode <natt/none/force-natt/cisco-udp>
--script <command>
command is executed using system() to configure the interface, routing and so on.
Device name, IP, etc. are passed using environment variables, see README. This
script is executed right after ISAKMP is done, but before tunneling is enabled. It
is called when vpnc terminates, too
Default: /usr/share/vpnc-scripts/vpnc-script
conf-variable: Script <command>
--dh <dh1/dh2/dh5/dh14/dh15/dh16/dh17/dh18>
name of the IKE DH Group
Default: dh2
conf-variable: IKE DH Group <dh1/dh2/dh5/dh14/dh15/dh16/dh17/dh18>
--pfs <nopfs/dh1/dh2/dh5/dh14/dh15/dh16/dh17/dh18/server>
Diffie-Hellman group to use for PFS
Default: server
conf-variable: Perfect Forward Secrecy <nopfs/dh1/dh2/dh5/dh14/dh15/dh16/dh17/dh18/server>
--enable-1des
Deprecated: Please use --enable-weak-encryption instead.
conf-variable: Enable Single DES
--enable-weak-encryption
enables weak encryption methods (such as DES, 3DES)
conf-variable: Enable weak encryption
--enable-no-encryption
enables using no encryption for data traffic (key exchanged must be encrypted)
conf-variable: Enable no encryption
--enable-weak-authentication
enables weak authentication methods (such as MD5)
conf-variable: Enable weak authentication
--application-version <ASCII string>
Application Version to report. Note: Default string is generated at runtime.
Default: Cisco Systems VPN Client 0.5.3+git20220927-1build2:Linux
conf-variable: Application version <ASCII string>
--ifname <ASCII string>
visible name of the TUN/TAP interface
conf-variable: Interface name <ASCII string>
--ifmode <tun/tap>
mode of TUN/TAP interface:
• tun: virtual point to point interface (default)
• tap: virtual ethernet interface
Default: tun
conf-variable: Interface mode <tun/tap>
--ifmtu <0-65535>
Set MTU for TUN/TAP interface (default 0 == automatic detect)
conf-variable: Interface MTU <0-65535>
--debug <0/1/2/3/99>
Show verbose debug messages
•
0: Do not print debug information.
•
1: Print minimal debug information.
•
2: Show statemachine and packet/payload type information.
•
3: Dump everything excluding authentication data.
• 99: Dump everything INCLUDING AUTHENTICATION data (e.g. PASSWORDS).
conf-variable: Debug <0/1/2/3/99>
--no-detach
Don't detach from the console after login
conf-variable: No Detach
--pid-file <filename>
store the pid of background process in <filename>
Default: /run/vpnc.pid
conf-variable: Pidfile <filename>
--local-addr <ip/hostname>
local IP to use for ISAKMP / ESP / ... (0.0.0.0 == automatically assign)
Default: 0.0.0.0
conf-variable: Local Addr <ip/hostname>
--local-port <0-65535>
local ISAKMP port number to use (0 == use random port)
Default: 500
conf-variable: Local Port <0-65535>
--udp-port <0-65535>
Local UDP port number to use (0 == use random port). This is only relevant if
cisco-udp nat-traversal is used. This is the _local_ port, the remote udp port is
discovered automatically. It is especially not the cisco-tcp port.
Default: 10000
conf-variable: Cisco UDP Encapsulation Port <0-65535>
--dpd-idle <0,10-86400>
Send DPD packet after not receiving anything for <idle> seconds. Use 0 to disable
DPD completely (both ways).
Default: 300
conf-variable: DPD idle timeout (our side) <0,10-86400>
--non-inter
Don't ask anything, exit on missing options
conf-variable: Noninteractive
--auth-mode <psk/cert/hybrid>
Authentication mode:
• psk: pre-shared key (default)
• cert: server + client certificate (not implemented yet)
• hybrid: server certificate + xauth (if built with openssl support)
Default: psk
conf-variable: IKE Authmode <psk/cert/hybrid>
--ca-file <filename>
filename and path to the CA-PEM-File
conf-variable: CA-File <filename>
--ca-dir <directory>
path of the trusted CA-Directory
Default: /etc/ssl/certs
conf-variable: CA-Dir <directory>
--target-network <target network/netmask>
Target network in dotted decimal or CIDR notation
Default: 0.0.0.0/0.0.0.0
conf-variable: IPSEC target network <target network/netmask>
--password-helper <executable>
path to password program or helper name
conf-variable: Password helper <executable>
--print-config
Prints your configuration; output can be used as vpnc.conf
FILES
/etc/vpnc.conf /etc/vpnc/default.conf
The default configuration file. You can specify the same config directives as with
command line options and additionally IPSec secret and Xauth password both
supplying a cleartext password. Scrambled passwords from the Cisco configuration
profiles can be used with IPSec obfuscated secret and Xauth obfuscated password.
See EXAMPLES for further details.
/etc/vpnc/*.conf
vpnc will read configuration files in this directory when the config filename (with
or without .conf) is specified on the command line.
EXAMPLES
This is an example vpnc.conf with pre-shared keys:
IPSec gateway vpn.example.com
IPSec ID ExampleVpnPSK
IKE Authmode psk
IPSec secret PskS3cret!
Xauth username user@example.com
Xauth password USecr3t
And another one with hybrid authentication (requires that vpnc was built with openssl
support):
IPSec gateway vpn.example.com
IPSec ID ExampleVpnHybrid
IKE Authmode hybrid
CA-Dir /etc/vpnc
or
CA-File /etc/vpnc/vpn-example-com.pem
IPSec secret HybS3cret?
Xauth username user@example.com
Xauth password 123456
The lines begin with a keyword (no leading spaces!). The values start exactly one space
after the keywords, and run to the end of line. This lets you put any kind of weird
character (except CR, LF and NUL) in your strings, but it does mean you can't add comments
after a string, or spaces before them.
In case the the CA-Dir option is used, your certificate needs to be named something like
722d15bd.X, where X is a manually assigned number to make sure that files with colliding
hashes have different names. The number can be derived from the certificate file itself:
openssl x509 -subject_hash -noout -in /etc/vpnc/vpn-example-com.pem
See also the --print-config option to generate a config file, and the example file in the
package documentation directory where more advanced usage is demonstrated.
Advanced features like manual setting of multiple target routes and disabling
/etc/resolv.conf rewriting is documented in the README of the vpnc package.
AUTHOR
This man-page has been written by Eduard Bloch <blade(at)debian.org> and Christian Lackas
<delta(at)lackas.net>, based on vpnc README by Maurice Massar <vpnc(at)unix-ag.uni-kl.de>.
Permission is granted to copy, distribute and/or modify this document under the terms of
the GNU General Public License, Version 2 any later version published by the Free Software
Foundation.
On Debian systems, the complete text of the GNU General Public License can be found in
/usr/share/common-licenses/GPL.
SEE ALSO
pcf2vpnc(1), cisco-decrypt(1), ip(8), ifconfig(8), route(1),
http://www.unix-ag.uni-kl.de/~massar/vpnc/