In general in these situations, there's something changing the message 
between the time the filter affixes the signature header and its receipt 
at a verifier.

As I'm unfamiliar with postfix, I'm left to guess at what that might be in 
your environment.  With sendmail, for example, there are features which 
alter the headers to do things like replace your fully-qualified hostname 
with your outward-facing domain name.  Unfortunately features like this, 
though aesthetically pleasing, thwart digital signatures that involve the 
changed headers, such as DKIM.  You should audit your postfix 
configuration to see if any of the features you're using there might cause 
something like this to happen.

Another thing you can try is to activate the "Diagnostics" feature.  This 
causes a copy of your signed headers to be included in the signature. 
Then at a verifier, it's possible to see what changed between the headers 
that got signed and the ones seen on arrival.  You would just need to send 
to a verifier that either automatically makes that analysis, or is run by 
someone who can do so manually.  Let me know if you need that facility 
and I can set one up.

There's some much more detailed debugging you can activate as well, but 
I'll explain that process later if these two steps don't solve the 
problem.

-------------------------------------------------------------------------
This SF.net email is sponsored by: Microsoft
Defy all challenges. Microsoft(R) Visual Studio 2008.
http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
_______________________________________________
dkim-milter-discuss mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/dkim-milter-discuss

Reply via email to