table of contents
VPNC(8) | System Administration Utilities | VPNC(8) |
NAME¶
vpnc - client for Cisco VPN3000 Concentrator, IOS and PIXSYNOPSIS¶
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
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
- --id <ASCII string>
- your group name
- (configfile only option)
- your group password (cleartext)
- (configfile only option)
- your group password (obfuscated)
- --username <ASCII string>
- your username
- (configfile only option)
- your password (cleartext)
- (configfile only option)
- your password (obfuscated)
- --domain <ASCII string>
- (NT-) Domain name for authentication
- --xauth-inter
- enable interactive extended authentication (for challenge response auth)
- --vendor <cisco/netscreen>
- vendor of your IPSec gateway
- Default: cisco
- --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
- --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
- --dh <dh1/dh2/dh5>
- name of the IKE DH Group
- Default: dh2
- --pfs <nopfs/dh1/dh2/dh5/server>
- Diffie-Hellman group to use for PFS
- Default: server
- --enable-1des
- enables weak single DES encryption
- --enable-no-encryption
- enables using no encryption for data traffic (key exchanged must be encrypted)
- --application-version <ASCII string>
- Application Version to report. Note: Default string is generated at runtime.
- Default: Cisco Systems VPN Client 0.5.3r550-2:Linux
- --ifname <ASCII string>
- visible name of the TUN/TAP interface
- --ifmode <tun/tap>
- mode of TUN/TAP interface:
- •
- tun: virtual point to point interface (default)
- •
- tap: virtual ethernet interface
- Default: tun
- --ifmtu <0-65535>
- Set MTU for TUN/TAP interface (default 0 == automatic detect)
- --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 exluding authentication data.
- •
- 99: Dump everything INCLUDING AUTHENTICATION data (e.g. PASSWORDS).
- --no-detach
- Don't detach from the console after login
- --pid-file <filename>
- store the pid of background process in <filename>
- Default: /var/run/vpnc.pid
- --local-addr <ip/hostname>
- local IP to use for ISAKMP / ESP / ... (0.0.0.0 == automatically assign)
- Default: 0.0.0.0
- --local-port <0-65535>
- local ISAKMP port number to use (0 == use random port)
- Default: 500
- --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
- --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
- --non-inter
- Don't ask anything, exit on missing options
- --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
- --ca-file <filename>
- filename and path to the CA-PEM-File
- --ca-dir <directory>
- path of the trusted CA-Directory
- Default: /etc/ssl/certs
- --target-network <target network/netmask>
- Target network in dotted decimal or CIDR notation
- Default: 0.0.0.0/0.0.0.0
- --password-helper <executable>
- path to password program or helper name
--print-config
- Prints your configuration; output can be used as vpnc.conf
FILES¶
/etc/vpnc.conf /etc/vpnc/default.confThe 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/September 2014 | vpnc version 0.5.3 |