Check the below video for more info
http://www.youtube.com/watch?v=5HLtTxb1n5Y
the most good thing is that you can ask for custom port either on udp or on tcp, that's even for free, and that's a good thing if a particular service provider block some particular ports ... currently there supported ports are:
UDP
53, 1194, 80,
443, 8080, 55,
5000, 9200, 50,
& Custom
TCP
53, 1194, 80,
443, 8080, 55,
5000, 9200, 50,
& Custom
to use it free with Airtel use any UDP port, for reliance use your correspondence port which is free for you, since docomo's vpn trick has been banned you can check varities of ports to get it worked, same applies to other service providers.
to get FREE VPN and all other information visit: http://vpnvilla.com