Problems with relaying email...

[Neil Rickert]

In article <1991Apr24.134148.24430 at ucunx1.san.uc.edu> Don.Rainwater at UC.Edu writes:
>
>	I'm having some problems with mail from my Ultrix 4.1 system.
>Apparently, the headers aren't coming out quite right.  The "real" From:
>header seems to be okay, since it comes out as username at ucunix.san.uc.edu
>(as it should).  However, up above this in the headers is another line
>that contains username at ucunix.  The name of this header line is called
>either From or Return-path:, depending on the receiving machine.  When
>it's a Return-path line, the address is enclosed in <>.

  This sounds like a configuration error on the Ultrix system.  It is the
responsibility of that system to ensure that all mail leaving the system
has proper return address, meaning fully qualified domain names.  You
will need to look at the mailer definition for the mailer being used to
send out this mail.  The mailer definition line begins with 'M', and you
can determine which mailer is being used by sending mail with /usr/ucb/Mail
using the '-v' (verbose) option.

  Once you have found the mailer definition, you will see it probably contains
something like
Mtcp, P=[IPC], F=CDFMXhnmu, S=12, R=11 .........

 The 'S=' operand is the one to look for.  That is the ruleset used to rewrite
the sender addresses.  Actually, it is used for both the 'From:' header,
and for the envelope address used in the 'Return-Path:' line.  But there are
some subtle difference which may account for what is happening.

 Assuming this is mail originating on the Ultrix system, the envelope
sender address starts as 'username', and is then reprocessed by the sequence
of rewrite rulesets:  3,1,4,3,1,12,4   (where 12 should be replaced by whatever
your mailer definition specifies).  The 'From:' header, on the other hand, is
probably being rewritten with the sequence of rulesets: 3,1,4,3,1,12,4,3,1,12,4.
In some cases, it may be rewritten only with 3,1,12,4.

 There is probably something peculiar in your rulesets 1 or 12, so that whether
the address goes through that ruleset an odd number or an even number of
times changes its format.  You will probably need to do some testing with
'sendmail -bt' to track this down.

-- 
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  Neil W. Rickert, Computer Science               <rickert at cs.niu.edu>
  Northern Illinois Univ.
  DeKalb, IL 60115                                   +1-815-753-6940