Andy said:
> Callouts have been "invented" to ensure that your mailer daemon is
> able to return an error message to the sender, should anything go
> wrong. They will not only discover invalid addresses, but also some
> kinds of misconfiguration of the remote MTAs (as in your case).
> Spamassasin is a real spam filter. The drawback is that, in order to
> use SA, you will have to receive the message first, then deal with it.
> Callouts OTOH will reject the mail *before* it enters your server. I
> currently prefer the latter, even if it sometimes bounces legit mail.
Hi guys,
I've been using callouts here for about two years, and while I have
found them to be immensely effective I can second the comment that
Imail servers are frequently a problem. There is a reference
to the issue here at the bottom of this link:
http://support.ipswitch.com/kb/IM-19980116-DD02.htm
I use this as a reference when I have to contact postmasters of sites
running Imail that are failing on callouts.
Additionally I have been running spamassassin with sa-exim:
http://marc.merlins.org/linux/exim/sa.html
to allow messages to be rejected during the smtp transaction. If it
is detected as spam by spamassassin, it never enters our transport queue.
This has proved very successful in filtering spam. We've been rejecting
about 2000 spam messages every 24 hours (about 20% of our total traffic).
I would be happy to provide any further details or anecdotes!
Thanks,
Tom
