I have a customer, a hotel that has a non-secured wireless network for their guests to use to access the internet. Currently it's just a Cisco router and a series of wireless access points. The problem we are having is that guests are showing up with infected laptops and using the internet connection to unknowingly blast out mail viruses in particular. The ISP is getting annoyed and wants us to do something about it.
I thought about limiting outbound tcp/25 access to the mail servers of the ISP only. But then most customers probably woudn't be savvy enough to change their outbound mail server and would just experience it as mail not working properly.
Alternatively I know that I could put a Barracuda hardware virus filter box in place and that would do the trick. But at several thousand dollars that's way more than this customer wants to spend. Does anyone know if there's a cheap Linksys-style box that would do more or less the same thing? Basically I just need some in-line solution that will detect virus traffic and kill it, getting the ISP off our backs.