Virus Software for windows 2000 server

[sjxm9203]

I am setting up a server for our small network, and I need to get virus software for our 2000 server system. However, each of our workstations already has Norton Anti-virus installed, so I do not want to purchase a small business pack from norton, because I will be buying double virus protection for all of my workstations.

Does anyone, know about an anti-virus software that runs on windows 2000 server, where I need to buy just one liscence to use on my server?

Thanks

sjxm