[Mimedefang] Sendmail::Milter

David F. Skoll dfs at roaringpenguin.com
Wed Nov 25 19:07:50 EST 2009

Kevin A. McGrail wrote:

>> I do something similar - daily LDAP extraction to a database table,
>> which my filter queries from filter_recipient.  I want to be able to
>> log failed messages from within my filter, so Sendmail's rejection via
>> the Access database is too crude for me.  All of my mail servers query
>> the same database, and also use the database to share
>> blacklist/greylist/whitelist data, etc.

> Sure, that will technically will work fine but I think DFS will agree
> with the statement "Holy Overhead Batman!"

Ehhmm.. :-)

Our commercial product offers a huge variety of mechanisms for validating

1) You can use LDAP lookups.

2) You can do an SMTP callout against a back-end SMTP server.

3) You can do a database lookup (PostgreSQL).

4) You can supply an arbitrary script that validates the recipient.

We need the flexibility because of the wide array of mail systems and
topologies.  On our hosted solution, we cache lookups using memcached
for efficiency (valid recipients are cached for 24h; invalid ones for

Yeah, way more overhead than /etc/mail/access, but in this case it is
worth it.



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