why rewrite From header?

[Matt Kettler]

<x-flowed>
At 02:28 PM 10/19/2004, Tim Myers wrote:
>Our web server uses DNS CNAME entries for its virtual hosts. Messages sent
>from those virtual hosts are having their From: headers rewritten using the
>A record hostname.
>
>CNAME records are not IP spoofing, why are they being rewritten?

Are you sure they are being rewritten and aren't being written that way in
the first place? Are you sure they contained the cnamed hostname in the
From: header when they were queued?

Very few things will re-write the From header, unless the domain-name part
is missing entirely, in which case most MTA's will rewrite the header
automatically for correctness sake.   (ie: From: mkettler gets rewritten to
From: mkettler at xanadu.evi-inc.com, but From: mkettler at evi-inc.com does not
get rewritten)

My MailScanner/Sendmail setup handles multiple domains just fine without
rewriting anything, except the above "username only" case.

------------------------ MailScanner list ------------------------
To unsubscribe, email jiscmail at jiscmail.ac.uk with the words:
'leave mailscanner' in the body of the email.
Before posting, read the MAQ (http://www.mailscanner.biz/maq/) and
the archives (http://www.jiscmail.ac.uk/lists/mailscanner.html).
</x-flowed>