Spam Filtering - How do you do it?

[tomp]

We've been getting quite a few inquiries into effective spam filtering solutions as of late. While I have my own ideas as to what works and what doesn't I wanted to poll our customer base to see what works for you. So, throw out your ideas and suggestions for what you do to combat the ever increasing amount of spam flowing into your inbox.

Tom

[sliqua]

I use a combination of Spamassassin and a Mailfoundry anti-spam appliance. I couldn't be happier with it, and for small businesses that don't want to drop the $700 - $14,000 for the appliance along with the associated costs of co-locating it, paying for updates, etc. There are a few companies offering hosted solutions from around $10-20 that relay spam-free mail to wherever your sites are hosted. Pretty slick deal =]

While it is just about impossible to stop every spam from getting through, my solution works very well. I utilize the following DNSBLs on the server-side as well:

relays.ordb.org
sbl-xbl.spamhaus.org
list.dsbl.org
multihop.dsbl.org
spam.dnsrbl.net
blackholes.easynet.nl
proxies.blackholes.easynet.nl
cbl.abuseat.org


Hope this helps, by the way, I want the BMW (http://myriadnetwork.com/forums/showthread.php?t=211), Tom =]

Cheers!
-Alex

[John]

Hi Alex,

Have you ever tested to see just how effective the appliance is alone? I've always wondered how those dedicated appliances stacked up to their open-source counterparts.

[sliqua]

John,

Yes, I have tested just an appliance alone. The issue really being that if you have a secondary MX record pointed to your mail server, a lot of spammers tend to use it rather than going through the appliance. That is the primary reason for using spamassassin and a few DNSBLs on the local server.

However! I did try out your idea a while back without spamassassin running on the locla server, and the mail foundry managed to wipe out over 99.5% of the incoming spam before it even hit the local box. In addition to that, Mail Foundry isn't like other antispam appliances, the database is actually maintained by real people rather than being automated. Thus, the chance of having a false-positive is like one in a million e-mails.

-Alex

[John]

Hi Alex,

I guess those appliances really do work then. I'd be interesting to see how the Mail Foundry appliance stacks up against SpamAssassin if each were used in a parallel, not series, configuration.

Have you ever used the Barracuda appliances? I know they're pretty expensive.

[sliqua]

No, I've never personally used one of them but would love to try one out eventually. A friend of mine referred me to try out Easy Antispam, which is a hosted Mail Foundry solution that is $19.95/server/mo for up to 500,000 processed messages. The only issue I have with it is that it is a single mailfoundry appliance and there is no sort of backup MX records for the service. However, i've never had less spam =]

[Dustin]

For a long time I used a combination of SpamAssassin and Thunderbird's filters, and it seemed to work well. Recently I've been using Gmail for portability reasons, and I have to say that I'm impressed with the job it did with the mail I began forwarding to it.

[sliqua]

For a long time I used a combination of SpamAssassin and Thunderbird's filters, and it seemed to work well. Recently I've been using Gmail for portability reasons, and I have to say that I'm impressed with the job it did with the mail I began forwarding to it.

Honestly, I have more spam that is able to get through Gmail's filters than a combination of my mailfoundry and spamassassin setup. Which is surprising considering the amount of users that use and report spam to Gmail. :eek:

[SixtyClear]

What company provides this hosted MailFoundry service?

EDIT: Just noticed you use Easy AntiSpam.

What solution do you guys use @ Myriad, Tom, Jeff?

[Jeff]

Though here and there I read people saying it's dated, SpamAssassin is still great. Thunderbird's spam filtering mechanism is also remarkably accurate. I've had very few false positives with it. ASSP (assp.sourceforge.net) sounds very promising as well - I've read nothing but very positive reviews of it.

[SixtyClear]

I quite like the look of Heluna (http://www.heluna.com).

Might give them a try this week at some point.

[erich]

If you try Heluna, please let us know if you like it.

[sliqua]

Just a quick update... I use Postini now instead of MailFoundry. IMO it's a lot more accurate (and cost effective).