[Mimedefang] Which first: stream_by_x or virus checks?
kelson at speed.net
Wed Oct 17 20:01:03 EDT 2007
Okay, I need a sanity check, here.
We've got a setup where almost everyone has the same filtering
parameters, but some users have custom thresholds, etc. What we've been
doing is checking whether the list of recipients includes one of these
users, and if so, running stream_by_recipient. This was fairly early in
We also run our virus scanning in filter_begin. Based on the name
returned by Clamd, we either discard (if it looks like a mass-mailer) or
reject. Since adding the SaneSecurity signatures, which uses the Clam
engine to identify spam, there've been a lot more rejects than there
used to be.
You can probably see where this is going.
Streaming first, then scanning for viruses, means that a message gets
resent locally, *then* rejected. So lost messages pile up in the client
queue directory, warnings pile up in the logs, and bounce notices get
I'm moving the calls to stream_by_recipient *after* the virus scanning
logic (but still in filter_begin). The downside is that anything clean
gets scanned N+1 times instead of N. It also means that if we ever want
to enable per-recipient reactions to clamd results, we'll need to move
it back. On the plus side, anything that does trigger Clam is only
scanned once instead of N times, and can be rejected immediately instead
of clogging the client queue.
Does this seem like a reasonable approach?
SpeedGate Communications <www.speed.net>
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