Sometimes you need to access resources on OSU network but you are outside the network, and you are using Linux. OSU provides us Cisco AnyConnect VPN Client 2.4 for Linux, which can be downloaded from the SLS website. However, for Debian users, it is more straightforward to use vpnc to access the VPN, since it's already in the standard repository. Another reason to use vpnc is that, the software downloaded from SLS is not compatible to my amd64 squeeze, i.e., it doesn't run on my laptop. After installing vpnc using apt-get install vpnc, there are just few steps before you can connect to the VPN.
No information on the 8help page is provided for the configuration of vpnc, which does not surprise me since Linux is not officially supported by OSU. Peeking at the settings in the Windows version Cicso VPN software will help you to create the corresponding configuration file in /etc/vpnc directory for vpnc. A configuration file (with extension file name .conf) should be created in the directory:
Local Port 0
IPSec gateway vpn.service.ohio-state.edu
IPSec ID <find_it_in_pcf>
IPSec secret <find_it_in_pcf>
IKE Authmode psk
Xauth username <your_osu_username>IPSec ID is the GroupName field in the PCF file of Cisco VPN client, while the IPSec secret is the GroupPwd field in the PCF file. You can find the PCF file in the directory you installed the Cisco VPN client that OSU provides. GroupPwd is encrypted, but there's a way to decrypt it, or you can ask OIT.
After filling all relevant information for the configuration file, you can start the VPN by using vpnc <conf_file_name> with root privilege. vpnc will prompt for your password every time when connecting. Warning, although Xauth password can be used to specify your personal credential to the VPN, for security reason, you should not really write it in the configuration file. You can verify the routing table by using route. You should see the tun0 device is added into the routing table for OSU network.
To disconnect from the VPN, use vpnc-disconnect with root privilege. Do not forget to disconnect before suspend/hibernate your laptop.