[Closed] IT Forum: Spam Filters

MessageLabs if you can afford it. All our incoming and outgoing mail passes through them (and the FW/Exch is locked to only their IP range for SMTP).

Else, if you have the knowledge, SpamAssasin ( http://www.howtoforge.com/linux_spam_filter_mail_gateway ) in the DMZ before your Exchange box.

EDIT: Slightly more recent link -> http://www.howtoforge.com/installing-assp-anti-spam-smtp-proxy-on-ubuntu-server-10.04-debian-5.0

Cheers xiphon. I've just discovered our built in filters weren't even turned on 🙄 so we'll see how that goes and then I'll take a look at one of those. Thanks

The main advantage of using an external spam filter, is the spam doesn't clog up your bandwidth.

We get around 15,000 spam emails per day.... but they get stopped at ML.

Dread to think how much bandwidth we would get stolen from us.....

All other things being equal, I'd second what Xiphon said and recommend an external service such as MessageLabs these days.

There's a number of advantages (and a couple of disadvantages) to doing this. Not least of which is, you palm off the admin headache to someone else.

On the email servers I see these days, I'd say that maybe 80% of all email is spam and malware, perhaps higher than that even. Each mail has to be routed, analysed, processed, categorised etc. which uses system resources. By doing spam handling locally, you'll need a server four or five times more powerful just to deal with crap you're going to throw away.

You've got the benefit of pooled heuristics (so your filters can learn from other people's spam as well as your own). This can be a double-edged sword though; for instance, I've worked for a financial company where legitimate emails look a lot like 'make money fast' type spam.

Cheers for that. We're quite small so it's not a massive issue - tens rather than thousands of messages a day. I don't even see them, it's my boss who's getting annoyed at deleting stuff out of his inbox.

That's probably a direct result of his Internet browsing habits. Pointing this out to him should stop the complaints.

Yeah messagelabs makes the most sense, we did used to maintain our own in-house ones using Mail Marshal but it's a lot of hassle for a small company to maintain (we used to run it for hosted client systems and charge for the privilege but switched to messagelabs as was actually cheaper to run in the longer term).

I've been looking at the offering from SpamExperts a bit recently. Generally pretty good and they're a nice bunch too. Pricing depends entirely on how many domains you need it for though.

We get around 15,000 spam emails per day.... but they get stopped at ML.

I don't even see them, it's my boss who's getting annoyed at deleting stuff out of his inbox.