We're using SpammerTrap from SECNAT and are very pleased with it. Runs on a dedicated PC in our datacenter but before our firewall and they actively update and tweak the settings remotely and run interference for us vis-a-vis the Internet. But we have as much control as we want internally, so we can globally or even down to an individual basis maintain white and black lists (we have a few people in marketing who actually WANT to receive all their spam, though we only allow them to receive the spam that makes it through the initial screen as harmless). So, for us, it's a nice combination of hardware-based and actively maintained pre-firewall screening and interface/representative to the Internet writ large and a lot of internal flexibility in allowing customized solutions for our staff. Everyone, for example, gets 2 emails a day with "questionable" email headers--emails that got picked out at the very last stage of screening--which one can scan through and delete, if they're all truly spam (and almost invariably they are), or one can "release" individual items, which allows them to pass through; and one can also individually black or white list and i.d. as spam or not spam each item, if they want to go to that trouble, so that the spam filter becomes "smarter" over time. Nice because individuals can then help refine the filters for the institution as a whole, ultimately.
Don't recall the cost, but not unreasonable at all--less than we were paying for Symantec's product--with an upfront cost (maybe $3k??) and a modest subscription fee, I think. Jerry Jerry Powell Director of Information Systems Winterthur Museum & Country Estate Winterthur, DE 19735 (302) 888-4751
