Debugging [Was Re: Using KeyTable]

From: Todd Lyons <>
Date: Tue, 25 May 2010 12:13:08 -0700

On Tue, May 25, 2010 at 11:36 AM, Todd Lyons <> wrote:
>>> So _something_ is changing that Sender header after the signature is
>>> generated.  I have not been able to isolate where the change is
>> Good sleuth work.  It would be interesting to know which piece of software is making that change, especially post-signing.  This would be useful for our README.
> I'll create the test list again, turn on KeepTemporaryFiles and see if
> I can spot something.

Did some debugging. Sendmail must be changing it. This is the
canonicalized Sender header that opendkim is signing:

And this is the Sender header that is in the received email:

If it's useful:

# rpm -q sendmail

... on CentOS 5.5.

Here is the technical detail of the Mailman hostname setting that is
uses to create that Sender header:
======= BEGIN
host_name (general): Host name this list prefers for email.

The "host_name" is the preferred name for email to mailman-related
addresses on this host, and generally should be the mail host's
exchanger address, if any. This setting can be useful for selecting
among alternative names of a host that has multiple addresses.
======= END

I have it set to "", whereas the machine hostname is (both are in the local-host-names w class file). So
for some reason, sendmail is rewriting the Sender header that Mailman
created (and signed) to the machine hostname. I do not have any kind
of Masquerading or genericstable configured, so I am unsure why
sendmail is doing that. To be more exact, I don't have any deep or
meaningful experience with the Sender header specifically, so I am
unsure if this is even expected behavior.

I have attached the canonicalized headers from the KeepTempFiles
setting, if it's useful.

Regards...      Todd
I seek the is only persistence in self-delusion and
ignorance that does harm.  -- Marcus Aurealius

Received on Tue May 25 2010 - 19:13:19 PST

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