VPNC(8) System Administration Utilities VPNC(8)NAMEvpnc - client for Cisco VPN3000 Concentrator, IOS and PIX
SYNOPSISvpnc [--version] [--print-config] [--help] [--long-help] [options]
[config files]
DESCRIPTION
This manual page documents briefly the vpnc and vpnc-disconnect com‐
mands.
vpnc is a VPN client for the Cisco 3000 VPN Concentrator, creating a
IPSec-like connection as a tunneling network device for the local sys‐
tem. 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 tunnel‐
ing 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 net‐
works are added to the routing table. Otherwise the default-route will
be modified to point to the tunnel. Further a host route to the con‐
centrator 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 previ‐
ously 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 com‐
mand-line vpnc will read configuration from stdin. The configuration
is parsed and the connection proceeds when stdin is closed or the spe‐
cial 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>
(configfile only option)
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>
(configfile only option)
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>
vendor of your IPSec gateway
Default: cisco
conf-variable: Vendor <cisco/netscreen>
--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, com‐
monly 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 envi‐
ronment 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>
name of the IKE DH Group
Default: dh2
conf-variable: IKE DH Group <dh1/dh2/dh5>
--pfs <nopfs/dh1/dh2/dh5/server>
Diffie-Hellman group to use for PFS
Default: server
conf-variable: Perfect Forward Secrecy <nopfs/dh1/dh2/dh5/server>
--enable-1des
enables weak single DES encryption
conf-variable: Enable Single DES
--enable-no-encryption
enables using no encryption for data traffic (key exchanged must
be encrypted)
conf-variable: Enable no encryption
--application-version <ASCII string>
Application Version to report. Note: Default string is generated
at runtime.
Default: Cisco Systems VPN Client 0.5.3r550-3: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 informa‐
tion.
·
3: Dump everything exluding 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: /var/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 com‐
mand 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 ALSOpcf2vpnc(1), cisco-decrypt(1), ip(8), ifconfig(8), route(1),
http://www.unix-ag.uni-kl.de/~massar/vpnc/
vpnc version 0.5.3 September 2014 VPNC(8)
