Cisco VPN

April 1st, 2020

Linux

Package requirement You will first need to get the vpnc package and install it. Fire up a terminal and enter this command:
```
  sudo apt-get install vpnc
```

Configuration file

  cd /etc/vpnc/
  cp default.conf mmw.conf
  #thu.iiis.co 166.111.129.132
  #gw.iiis.co  122.200.68.61 
  #
  IPSec gateway 122.200.68.61
  IPSec ID       <XXX>
  IPSec secret   <XXX> 
  IKE Authmode hybrid # <hybrid/psk/cert> 
  Xauth username <XXX> 
  Xauth password <XXX> 
  (Optional) NAT Traversal Mode natt # <natt/none/force-natt/cisco-udp>

Usage

Connecting to a VPN

e.g., sudo vpnc mmw --enable-1des --local-addr 10.227.4.22 --local-port 500
ubuntu@yc-ubuntu:/etc$ sudo vpnc mmw --enable-1des 
VPNC started in background (pid: 22892)...
ubuntu@yc-ubuntu:/etc$ ping 10.19.0.80
PING 10.19.0.80 (10.19.0.80) 56(84) bytes of data.
64 bytes from 10.19.0.80: icmp_seq=1 ttl=63 time=0.915 ms
64 bytes from 10.19.0.80: icmp_seq=2 ttl=63 time=0.764 ms
--- 10.19.0.80 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1030ms
rtt min/avg/max/mdev = 0.764/0.839/0.915/0.080 ms

If you get error: vpnc: response was invalid [2]: (ISAKMP_N_INVALID_EXCHANGE_TYPE)(7), it is because you false settings of authentication (hybrid instead of psk) so you have to change your .conf file as above meantioned. [1]

Disconnecting from a VPN
```
sudo vpnc-disconnect
```

Other platforms

macos
win10

More on decrypting the Group password [2]

http://www.unix-ag.uni-kl.de/~massar/bin/cisco-decode provides the source code use to decrypt the group password.

New VPN

Please refer to the following link. VPN User Guide

REF

Notes (10)