Let me talk of security over a Sify Connection. I am have a program which has a feature to sniff NICs over a network. i tried it on my Sify Connection and i got the list of all the online computers in my network. The result included PC name, MAC address and the local IP address. Isn't this information for some user in the network to hack into some another system or even a virus who can travel within the network.

Yep i once used hacked connection on sify also u can copy stuff from diffrent pc also u can trace yahoo chats including mails on sify ... VERY EASILY ..... dats da reason i quit n hate sify BB

Yep - even I've noticed the same on my friend's Sify connection, you can browse through computers linked on the same network. You'll have to install a good firewall ( the windows default firewall's not good enough), and antivirus to secure your pc on sify.

As you mentioned @zatang, yes viruses are rampant on the network and can spread across.

Oh, this is really bad. Earlier i had ZoneAlaram installed as Firewall and Antivirus. But i left it more than a year ago, then i switch to Avast and now since the few months i am using Nod 32 which is working perfect to catch the viruses. Any good firewall which can work along with Nod32 antivirus?

I used to use Comodo (http://www.personalfirewall.comodo.com/) when I was on Windows.

Can i use it along with Nod32? Next, if it possible to hack into LAN, then can i play LAN games with my friends on the sify network? Actually, i did it once and it was an utter surprise to me. I played Quake 3 over sify LAN network. But what was strange in that session that both of the connections were from different routers.

I'm sure it can - I actually haven't tried nod32.

When i played it last time, i didn't do anything to hack into my friend's LAN. It was just that his PC showed up in Quake 3 and we got connected.