Antispam solutions

[Eric Anderson]

Phillip Salzman wrote:
> Hello,
> 
> I've been researching several different vendors for antispam over the last
> few weeks.  It seems many of the major commercial players (Brightmail,
> Sophos) charge per-user rates that make it difficult to the bottom line.
> 
> One of the goals is to prevent the mail from actually hitting our backend
> Qmail systems, but at the same time give users the ability to weed through
> their messages in a quarantine.  Initially we wanted to deploy Spam Assassin
> but haven't found any quarantine method available.
> 
> So - my question is what some of you were using for ISP-based antispam, and
> do you know of a user-manageable quarantine for SA?  We have roughly 90k
> users and 11k domains.

What I do at our company, is I use blacklists on our 'external' mail gateway - so all mail coming in to the company hits it first, and most of the spam gets blocked using that.  I then have the gateway send all mail to a few internal mail hosts, which do virus scanning using clamav, and pass virus free mail on to my main mail server (which runs IMAP and POP services), which runs mail through spamassassin (spamc) but uses a second machine (running spamd) to do the processor intensive spam filtering.  The spamd machine has NFS access to the users' mail directories (mounted from the mail server) so each user can have customized spamassassin setups (or none at all), and custom bayes databases.  

This setup seems to be working quite well for us.  It is also very scalable, as we round robin the mail hosts (SMTP), the spamd server, etc.  You can have a large number of SMTP servers, and a large number of spamd servers, and even run some  vrrp or carp software on them for failover situations.


Eric



-- 
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Eric Anderson        Sr. Systems Administrator        Centaur Technology
A lost ounce of gold may be found, a lost moment of time never.
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