[Mimedefang] Dealing with massive spam burst

[Patric Wust]

> Has anyone come up with a 'pure sendmail' way to accomplish this?  That
> is, given a firewalled machine running sendmail, to periodically rebuild
> an access list containing all the addresses it will accept, and on the
> exposed machine a way to merge the lists from an assortment of
> destination machines? 

I rather use an event-driven than a periodically-run update.

I wrote a bash script which is invoked on any delivering local MTA 
each time an account or alias is changed. The script collects all 
relevant information (domains, accounts, aliases) from all in-house MTA,
and then sychronizes the data with sendmail's access, virtuser-domains, 
and virtusertable at the mailgateway.

Local MTA's are qmail, Gateway-MTA is sendmail with MIMEDefang. Works 
perfectly here. The effect of this was a reduction of incoming mail traffic 
by 80% only by revoking wrong recipients during the envelope part of a 
SMTP session. The remaining 20% are then handled by MIMEDefang.

Rgds,
Patric