17
09 | 2013
Google, your IPv6-related email restrictions suck
After years of waiting, Google has finally enabled IPv6 for their email service Gmail. And a few weeks ago, they updated their policy, adding one specific rule: reject email from IP addresses with no reverse name:
% nc -Cv gmail-smtp-in.l.google.com. smtp Connection to gmail-smtp-in.l.google.com. 25 port [tcp/smtp] succeeded! 220 mx.google.com ESMTP bz2si13656083wjc.108 - gsmtp HELO boo.example.com 250 mx.google.com at your service MAIL FROM: <me@example.com> 250 2.1.0 OK bz2si13656083wjc.108 - gsmtp RCPT TO: <you@gmail.com> 250 2.1.5 OK bz2si13656083wjc.108 - gsmtp DATA 354 Go ahead bz2si13656083wjc.108 - gsmtp Subject: Test From: Me <me@example.com> To: You <you@gmail.com> Test. . 550-5.7.1 [2001:db8:8e3f:43c7::12 16] Our system has detected that this 550-5.7.1 message does not meet IPv6 sending guidelines regarding PTR records 550-5.7.1 and authentication. Please review 550-5.7.1 https://support.google.com/mail/?p=ipv6_authentication_error for more 550 5.7.1 information. bz2si13656083wjc.108 - gsmtp