Good & free Exchange spam filter [closed]

If you don't mind an outsourced service, you may be able to use Safentrix as a gated filtering solution. They claim free service that scales up to 20,000 users. I have not tried this service, so your mileage my vary.

There are a slew of other paid gating services that you can use to filter your incoming mail such as MX Logic (have heard good things about them).

If you want an in-house solution, you could look at a hardware device such as a Barracuda, or a software solutions such as ModusGate.

We find that properly configured DNS/Realtime Black List (DNSBL/RBL) works wonders, part of the Intelligent Message Filter in Exchange 2003. We use:

• SpamHaus SBL+XBL+PBL: http://www.spamhaus.org/
• SORBS Dynamic IP Address Block List: http://www.sorbs.net/

See this article for how to configure it in Exchange 2003.

I don't know of many free products, although i have seen an implementation of spam assassin for exchange 2003. Most products are paid for ones, some to of the popular ones being:

• GFI Mail Essentials
• XWall Spam Filter
• Sunbelt Ninja Email Security

There's an article which provides a overview of some solutions to that issue.