Mail server

Related pages:

• IMAP
• Removing Maildir Duplicates
• SMTP

Troubleshooting

Google GMail - 421-4.7.0 black listing

References:

• https://www.rackaid.com/blog/gmail-blacklist-removal/
• Bulk Senders Guidelines
• Gmail Postmaster Tools
• http://whatismyipaddress.com/blacklist-check

We get in /var/log/mail.log:

Sep  5 08:29:11 ober postfix/smtp[8491]: 43B4F22205: host gmail-smtp-in.l.google.com[66.102.1.27] said: 421-4.7.0 [91.134.133.203      15] Our system 
has detected an unusual rate of 421-4.7.0 unsolicited mail originating from your IP address. To protect our 421-4.7.0 users from spam, mail sent from 
your IP address has been temporarily 421-4.7.0 rate limited. Please visit 421-4.7.0  https://support.google.com/mail/answer/81126 to review our Bulk 
Email 421 4.7.0 Senders Guidelines. jg8si2554443wjb.4 - gsmtp (in reply to end of DATA command)
Sep  5 08:29:11 ober postfix/smtp[8490]: 6FD32222D3: host gmail-smtp-in.l.google.com[66.102.1.27] said: 421-4.7.0 [91.134.133.203      15] Our system 
has detected an unusual rate of 421-4.7.0 unsolicited mail originating from your IP address. To protect our 421-4.7.0 users from spam, mail sent from 
your IP address has been temporarily 421-4.7.0 rate limited. Please visit 421-4.7.0  https://support.google.com/mail/?p=UnsolicitedRateLimitError to 
421 4.7.0 review our Bulk Email Senders Guidelines. d66si5510162wmc.138 - gsmtp (in reply to end of DATA command)

Looking the source message, we see it is due to a forwarder from twitter to a gmail account:

grep 43B4F22205 /var/log/mail.log.1|head
# Sep  1 16:52:22 ober postfix/cleanup[8522]: 43B4F22205: message-id=<A8.4B.18871.79048C75@twitter.com>
# Sep  1 16:52:22 ober postfix/qmgr[2449]: 43B4F22205: from=<b0045f3e0b2keccakontwitter=noekeon.org@bounce.twitter.com>, size=21136, nrcpt=1 (queue active)
# Sep  1 16:52:22 ober postfix/local[8524]: A18C5222D1: to=<keccakontwitter@noekeon.org>, relay=local, delay=5.9, delays=5.8/0/0/0.06, dsn=2.0.0, status=sent (forwarded as 43B4F22205)
# Sep  1 16:52:22 ober postfix/smtp[8531]: 43B4F22205: host gmail-smtp-in.l.google.com[64.233.166.26] said: 421-4.7.0 [91.134.133.203      15] [...]
# Sep  1 16:52:23 ober postfix/smtp[8531]: 43B4F22205: to=<guido.bertoni@gmail.com>, orig_to=<keccakontwitter@noekeon.org>, relay=alt1.gmail-smtp-in.l.google.com[173.194.222.26]:25, [...]
grep keccakontwitter /etc/aliases
# keccakontwitter: gvabulk, mip, jda, gbe
grep ^gbe /etc/aliases
# gbe: guido.bertoni@gmail.com

As reported here, the issue may be due to SPF, which "breaks" mail forwarding: we provide a mail with from address @twitter.com, but from a server that is not authorized by twitter.com. The solution is apparently to use SRS.

Install [postsrsd]

See Configuration Noekeon.org.