AV vendors have a vested interest in making sure that every computer in the world is running their software, so please take anything they tell you with a 50 lb block of salt. However, any computer exposed to the internet has
some degree of vulnerability, so some sort of anti-malware is preferable. Windows Home Server has a very small surface area, so exposure is relatively low; as a result leaving your sever with nothing is not the worst plan in the world.
All that said, just about any AV that will install should work, whether it's officially supported by the AV vendor or not; the drives in your server are no longer special because of Drive Extender. So if you like Forefront and can afford it, it should work.
Same for other offerings. I will warn you that if something goes wrong with your chosen AV, Microsoft and the AV vendor will almost certainly disclaim any responsibility unless the AV vendor claims full support and doesn't include a bunch of weasel
words in the EULA to effectively disclaim all responsibility. (Hint: last time I looked,
all AV vendors disclaim just about all responsibility if Bad Things™ happen.)
One AV you will not get working, I'm afraid, is Microsoft's free offering.
Regarding search: Try
this one. It's where the forum search (which is broken again) redirects when you search this forum for
AV antivirus. There are several hits on the first page that are pretty current.
I'm not on the WHS team, I just post a lot. :)
