Firewall needed

HI all,

this is adrehman

i am using windows 2000 server as our file server and internet server with internet connection sharing and thats working fine.

after that we have lot of viruses on our server and strang IP hits how acn i block unknowns to access my server and how can i make my server more secure.

please name the some firewall software and also Anti virus.

right now i am using Intel norton anti virus 2001.
but this is not working with Trojan viruses.

please i need help in this regards.

Adrehman
09221-625426