[Mimedefang] Performance Benchmarking / Experiances

Clayton, Nik [IT] nik.clayton at citigroup.com
Fri Sep 26 06:35:01 EDT 2003

>> Why aren't you using the access.db?  Sendmail will consult this, and 
>> reject the message if necessary without ever needing to send data to
>> a milter.  Doing IP/domain based blacklisting in MIMEDefang isn't 
>> terribly efficient -- although it has other benefits (keeping the data
>> in external databases, for example).
> Because we are NOT allowing outbound mail through this filtering cluster
> - it only accepts mail inbound to our 400 mail domains, so no relay
> check is required, only a check of the recipients.  Any recipient not on
> our mail domains gets a relay denied response.

Right, I understand that.  But in the message I replied to, you also

> We use filter_relay in mimedefang to check against a black list of
> spammers...

You can use the access.db for more than just relay checks.  If your
spammer blacklist is IP address, or domains, or even full e-mail 
addresses, you can list those in your access DB.  For example, this line;

    optamail.com            ERROR:5.7.1:554 Administratively blocked

will cause any mail from optamail.com to be rejected by Sendmail with
the listed error code and message, without Sendmail passing the message 
down to MimeDefang.  So you save the overhead of calling MimeDefang
through the milter interface, which can be significant on a busy server.

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