you can have a look to comodo. They offer a free Linux sw. For Linux there are not much virus on the road. Are you looking for Antivirus Program running on a linux file server ?
I had gone through the posts. I too searching for the best software which is as free of cost. My friend suggested me some of the software's which are as free of cost but those are not offering good features. If anyone had an experience with any software, Please share those details. Any kind of information is greatly accepted at any movement.