Gmail email blocking is off the rails (again)

Constantine A. Murenin mureninc at
Wed Dec 4 20:48:55 UTC 2019

I think at this point we should upgrade the classification of this
issue from being Spam-filter-related to being a fundamental
interoperability issue of Google Mail and G Suite with regards to
email and SMTP.

Google has a monopoly on corporate email nowadays (even OPs own domain
name is still handled by Gmail).  Google still "officially" supports
incoming SMTP, but they've otherwise made it non-interoperable with a
whole bunch of the operators.

Google still rejects email from my own domain name as outlined in a
prior message on this list a month or two ago:


Since I am able to receive email from Gmail, but not able to send it
back, I'm thinking of implementing my own handling of incoming SMTP
unique and specific to Gmail / G Suite — anytime anyone tries to send
me email from Gmail / G Suite, I'll accept the message, but instead of
providing a 2.0.0 confirmation at the end of the message body, will
instead provide a 5.0.0 DSN with an error message explaining to the
sender that I won't be able to reply back to them due to the
interoperability issues of Google Mail / G Suite on their side.  What
other choice do I have?

I just don't see any other way on how to proceed otherwise.  It's
especially annoying if you're using a certain platform to communicate
with someone (which automatically takes care of the notifications and
has its own email gateway), and then they switch the conversation to
direct email, but then you're no longer able to reply to their


> Cute way to promote Google Groups over Mailman.  Gotta give 'em credit
> for being creative :-)
> > For some reason Gmail has started blocking mailman administrative
> > emails to someone who's an admin on a list I host.  Their SMTP 552
> > error message points to
> > <>, which implies the
> > "problem" is the URLs in the email, but is otherwise completely unhelpful.
> >
> > If anyone here has any pull with Gmail postmasters, could you please
> > suggest to them that they whitelist messages that are as consistent
> > and well-known as mailman's admin and moderator messages?

More information about the NANOG mailing list