[Mimedefang] Exempting +nodefang addresses from defanging

[Jeffrey Goldberg]

I am very new to MIMEDefang, but am helping to maintain a site that it
running it through the sendmail/Milter mechanism.

I've been asked to set up special addresses that are exempt from
defanging.  That is, I need a mechanism by which one can send things that
would otherwise be quaranteened or discarded.

I was thinking of using something like "user+nodefang" as a tag for such
addresses.  Additionally, I was thinking of maintaining a file of local
users who were allowed to do this (so no known Outhouse users could use
this to get around defanging).

Anyway, this leads to a bunch of questions which I am now facing:

 o filter or filter_begin ?

   I could put something in filter that "accepts" anything to the right
   recipients, but it strikes me that it would be more efficient to
   just accept the message instead of having to separately accept each
   part.  So is there an easy way to put something in filter_begin that
   just says pass this message through with no further filtering?

 o Dealing with multiple recipients

   I see that throught the multiplexor mechanism (which I don't yet fully
   grok) I could probably do things on a recipient by recipient basis.
   But my inclination is to use the @Recipients list and simply skip
   defanging when all local recipients have been specified with +nodefang.

   Does that seem reasonable, or is there some problem with that that I
   haven't anticipated?

 o Testing configurations.

   How do I tinker with and test mimedefang-filter.pl
   without breaking mail delivery while testing?

 o Sequence with virus scanning and SpamAssassin

   The current set-up does not use any virus scanners, but does call
   SA for labelling from MIMEDefang.  And I plan to introduce virus
   scanning in the future.  My gut feeling is that I should still have
   the "+nodefang" addresses subject to SA and virus scanning.  This, I
   suppose, adds to the complication of my first question ("where do I
   put the exemption code?")

I've looked at the FAQ and the man page (currently 2.20 is installed; I'll
get the latest), and I've even made a pass at searching the list archives.
If there is something I've missed, please point me to it.  But I'd
appreciate all the help I can get.

Also I'd welcome comments on the wisdom of this sort of policy.  It makes
sense to me, but, as I said, I'm very new to MIMEDefang, and suspect that
there are things I haven't thought through.

-j

-- 
Jeffrey Goldberg                            http://www.goldmark.org/jeff/
 Relativism is the triumph of authority over truth, convention over justice
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