[Mailman-Users] Google mail servers reply "Multiple destination domains per transaction is unsupported "

Joseph Brennan brennan at columbia.edu
Fri Mar 8 16:06:31 CET 2013

Max Pyziur <pyz at brama.com> wrote:
> We received the following while sending out a newsletter/notification to
> a 6,000+ email list:
> <<< 451 4.3.0 try again. ac8si27848234obc.211 - gsmtp
> Deferred: 451-4.3.0 Multiple destination domains per transaction is
> unsupported.  Please ... while talking to aspmx.l.google.com
> This reads like a configuration issue on the those businesses and
> educational institutions who rely on Google mail servers.
> Is there a way for the sender (us) to be whitelisted, or is this matter
> handled at the receivers' end?

I reported this a few months ago, as a Google Apps for Edu customer, and 
Google refuses to fix it. I spent a couple of weeks back and forth with 
several people, and I got beyond the first line helpdesk. None of them 
could give me a good explanation, but they confirmed it is not considered a 
bug, it was done deliberately.

It means that if you send to two domains, both hosted at Google, they will 
accept only the first domain. To spell it out:

rcpt to:<name at columbia.edu>
250 2.1.5 OK k17si2328403qct.207 - gsmtp
rcpt to:<name at barnard.edu>
451-4.3.0 Multiple destination domains per transaction ...

The lucky domain named first gets their messages right away, and the others 
have to wait until you run the queue.

Joseph Brennan
Manager, Email and Systems Applications
Columbia University Information Technology

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