E-mail admins: What do you use for Spam filtering software?

Background:
I’m a systems admin for an school system. We were using IMail 7.0 and Declude Junk Mail for our E-mail and Spam filtering software. We have about 1600 mail accounts.

It stopped working properly, so I got a new server and installed hMailServer as our new E-mail software, and it works great, but Declude Junkmail won’t work with it. I have played around with ASSP as our spam filtering software, but even after 2 weeks of constant training, it still is misclassifying good messages as spam.

So I once again to go the SDMB.

E-mail admins: What spam filtering software do you use/have you used that you could recommend? My only requirements are that it is not too expensive (Say in the $300-$600 range… and that could be annually as well), relatively easy to configure, and has some options for end user configuration.

One of the best I’ve found is not actually software, it’s a service call Appriver. They’re a company you pay per user to filter spam and virii. Yearly cost. You have your email sent to them, they resend it to you after filtering. The admin can view what they filtered and send it on if necessary. When I used to be a consultant, I set it up for several companies and they all still use it. I wish I could get my company to use it, but that’s another story.

Biggest benefit is the lack of software, the admin doesn’t have to do updates or make sure anything is current, they handle that for you. Per user cost is pretty low, I think it’s like 40 cents a user.

NOTE: I have no affliation with them whatsoever. They just have always done a good job, and I’ve have good experiences with them.

I’ve never run it on Windows, but SpamAssassin is that Alpha and the Omega:

It’s free/libre.

I’m pretty happy with GFI MailEssentials. It’s got more than anti-spam, such as auto-replies, disclaimers, a list server, mail monitoring and basic archiving, and the anti-spam is pretty damn good.

Plus, it allows users to add things to black or white lists, and train the Bayesian filter themselves. (This might be a feature only available with Exchange, but the product does work in simple SMTP mode.)

Disclaimer I don’t work for GFI, etc, etc. I’m just happy with their entire suite of products.

We use Postini, it works great, and I think it’s cheap.

www dot postini dot com

diku:
I contacted Appriver’s sales dept and got some more information. It has some very nice features that do address our concerns about letgitimate mail getting caught, but the price tag for us ($6900 per year) might be too high.

black455:
I thought about trying Spam Assasin, but the time and effort to get it installed and configured on our Win2K server is too much for what I would like to involve myself with.

dasgupta:
GFI MailEssentials looks like it works similar to ASSP (from what I could tell of the description on the web site. Part of the problem we had with ASSP was that we have a large user base, but very few people actually willing to work with the baysean database filter to train it correctly. The end result was a product that continually misclassified good messages as spam.

Any more suggestions out there? I need a good pool of products/services to choose from so I can go to my boss as well informed as possible.

We’ve been using a small appliance/server (runs on Linux) called Doublecheck:

http://www.nmgi.com/doublecheck/

It has many, many configurable options and does an excellent job at stopping spam. Its very granular too, you can configure options down to the user level.

We use SurfControl for email filtering and internet monitoring (real time and retrospectively). I don’t remember it being particularly cheap, though.

I don’t know if there’s Windows software that implements it, but for my personal mail server, I’ve had more success with greylisting than anything else. Probably removed 90% of the spam I was receiving the moment I started using it.