New VPN system (https://sconnect.nic.in) has been introduced since August 2012. If you have not migrated to this new VPN system, then you are requested to do the same IMMEDIATELY. The old VPN system with legacy Cisco VPN client (vpnserver.nic.in / 18.104.22.168 & 91) will not be available after 31st January 2013.
You have to register online to get new Digital certificate. This application has to be filled under the guidance of the NIC coordinator and the .pdf file generated has to be signed by the user, recommending officer and NIC coordinator and forwarded to VPN support.