https://www.debuntu.org/how-to-connect-to-a-cisco-vpn-with-vpnc/

1. Installing vpnc

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

2. Creating a *.conf file

cd /etc/vpnc/
cp default.conf mmw.conf

Modify mmw.conf as follows:
(IIIS OpenStack)

#thu.iiis.co 166.111.129.132
#gw.iiis.co  122.200.68.61
IPSec gateway 166.111.129.132    
IPSec ID test
IPSec secret 123456
#IKE Authmode hybrid
Xauth username your_username
Xauth password your_password

3. Using a configuration file

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
^C
--- 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

4. Disconnecting from a VPN

Once connected, the client can be disconnected using:

sudo vpnc-disconnect