Spam Filtering

[raffi at flossyourmind.com (Raffi Jamgotchian)]

Astaro's AntiSpam suite is very affective solution IMHO. You just need  
to decide if you want all of that stuff being handled by your  
equipment or just killed before it even gets to you.

On May 19, 2009, at 7:13 AM, Jack Daniel wrote:

> As you might expect, I use an Astaro box...
>
> But, no sales pitch here- for SMTP filtering I have found Commtouch's
> anti-spam offerings to be very good.  Several commercial products
> (including Astaro) license Commtouch tech as a component in their
> offerings.  Theirs uses a combination of reputation and heuristics,
> works very well.
>
> There are some non-commercial anti-spam tools/techniques which are
> built into a variety of systems, look for them in the solutions you
> consider;
> BATV does a good job of managing "backscatter" spam (spoofed bounce  
> messages)
>
> Greylisting is very good at controlling bot-generated spam (requires
> an RFC-compliant retry to validate the server, then whitelists the
> server)
>
> SPF is the answer for spam which claims to originate from your own  
> domain(s),
>
> CONSERVATIVE RBLs (like Spamhaus) can be valuable, but many RBLs are a
> bit too aggressive for commercial use (that is, if you want to get
> email from your customers)
>
> RDNS checks are good, but you will occasionally run into misconfigured
> servers which you will have to deal with. Note: simple RDNS only
> requires the IP of the sending SMTP server have a hostname associated,
> it does not require SMTP to originate from an MX record IP for the
> domain.
>
> HELO/EHLO checks just make sure the sending server says "hi" in an
> appropriate manner, generally checking for valid hostname formats and
> such.  You will need some exceptions for older/misconfigured servers
> for this one, too.
>
> Mix and match the above as appropriate in whatever commercial or Open
> Source package, and you will have a happier MTA and inbox.
>
>
> Jack
>
>
>
>
> -- 
> ______________________________________
> Jack Daniel, Reluctant CISSP
> http://twitter.com/jack_daniel
> http://www.linkedin.com/in/jackadaniel
> http://blog.uncommonsensesecurity.com
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