Finnaly Cisco VPN working....

Here is my recipe:

1. Install network vpnc plugin for network manager.
2. According to the server you want to connect, you can have different settings to be made, in my case, i did the folowing:
                       
                        Gateway: vpnc url where your client will connect
                        Username: your username
                        Username Password: your username password
                        Group Name: Cisco vpn group configured at server site
                        Group Password: Cisco vpn group password

Well at this point  i was ready to go! Connecting and.... NOTHING....! Again and.... Nothing. Again and again! Some times i just hate my work. :)


3. Googling


After a few days googling i found some interesting information,  vpnc client would have to set is MTU to 500. So i talked with my guru for divine enlightenment (command man).... And exercised those teachings in terminal
Through sudo ifconfig check the characteristics of your network cards, and usually by default all are set to MTU 1500. So lets change the MTU size...



sudo ifconfig [networkcard] mtu 500

Guess what!!??!?! It worked!!!! I thought this MTU negotiation should be done automatically, i don't know why is not made, i don't know if it is a bug in network manager or is just supposed to work like this. If someone knows how to explain it. Please don't hesitate.

Even if you install the vpnc client (terminal mode), the problem remains, it just won't work, i add to change the network card MTU.

My regards to you all...


Links:
Wikipedia Maximum Transmission Unit
Network Manager
Cisco VPn Groups

Documentation
man ifconfig

Logs
tail -f /var/log/messages