[Mailman-Users] AOL screening Reply-To header thru DMARC ?

Ed Ravin eravin at panix.com
Sat Oct 18 07:33:59 CEST 2014

I'm setting up a new Mailman server to replace an elderly MajorDomo
that isn't DMARC-compatible.

I set up the list to use the list's address as the From address and to
put the sender's address in Reply-To:.  I started playing around with a
test list - in no time at all, AOL began bouncing all my mail.

After researching AOL's error messages, it appeared that my server
had been temporarily blacklisted.  That went away but then I noticed
this error:

   Oct 18 01:01:26 vc18 postfix/smtp[25098]: C77D416B4D9: host mailin-01.mx.aol.com[] said: 421 4.2.1 :  (RLY:SN) http://postmaster.info.aol.com/errors/421rlysn.html (in reply to end of DATA command)

According to that URL on AOL's site, either my From or Reply-To is using an
address in violation of DMARC.  I had already checked the From address so
it was apparent the Reply-To was at fault.  Aalthough the mail was not
being rejected, given AOL's hair-trigger sensors I figured it would be
better to do it their way.   Changing the  Reply-To: to the list's address
got rid of the 421 error.

Has anyone else run into this?  I hate doing this, since now we're going
to see people sending what they think are private messages to the entire

I see from the docs that Mailman can do different behavior on the From:
address depending on whether it is in a DMARC-protected domain - are there
any plans to do the same for the Reply-To?  Looks to me like it will be
necessary given what AOL is doing.


	-- Ed

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