Do not scan outgoing messages for spam

David Lee t.d.lee at
Fri May 23 10:04:08 IST 2008

On Thu, 22 May 2008, Devin Henderson wrote:

> Hi all. Im running the latest version of MailScanner on top of
> sendmail and SpamAssassin on CentOS 5.1. I want to avoid scanning any
> outgoing messages for spam because some of my users' outgoing mail is
> being marked as spam. How can I accomplish this?
> Also, I would like to recommend a new feature for future versions of
> MailScanner where scanning of outgoing and incoming messages can be
> enabled or disabled. i.e.:
> Scan Outgoing Messages = No
> Scan Incoming Messages = Yes
> Thanks. Looking forward to any help you guys can give me on this.

We tend to think of these things as about "how to protect ourselves".  But
there is also the issue of "how to help others".

Think briefly of viruses, rather than spam.  Presumably we all run
virus-scanning inbound, to protect ourselves from outside infections
coming in.  But I would also sincerely hope that we also run anti-virus
outbound to protect others, in case of a local infection (these things do
happen) leaking out.

So why not also with spam?  If a local account is compromised (can we
absolutely guarantee against it?) then the local site (yours, mine)
could start generating outbound spam.

So running anti-spam outbound is a "Good Thing".

And in helping others by doing outbound spam-checking the local site also
helps itself.  If a local compromise does happen, then the local site can
end up on anti-spam blacklists, getting our outbound email treated as spam
by its recipients.  Do we really want that?

You also say "some of my users' outgoing mail is being marked as spam".(*)
In that case, irrespective of anything else, it would be worth
investigating that and at least trying to understand it; it suggests your
local spam settings might need attention.

(*) How good to see the plural possessive apostrophe correctly placed!


:  David Lee                                I.T. Service          :
:  Senior Systems Programmer                Computer Centre       :
:  UNIX Team Leader                         Durham University     :
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