Отбойники от Gmail (проблема с ipv6 PTR)

Если приходят отбойники от Gmail типа:

This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its

recipients. This is a permanent error. The following address(es) failed:

[email protected]

   (generated from [email protected])

   SMTP error from remote mail server after end of data:

   host gmail-smtp-in.l.google.com [2a00:1450:4010:c03::1a]:

   550-5.7.1 [2a00:f940:2:1:2::55e] Our system has detected that this message does

   550-5.7.1 not meet IPv6 sending guidelines regarding PTR records and

   550-5.7.1 authentication. Please review

   550-5.7.1  https://support.google.com/mail/?p=ipv6_authentication_error for more

   550 5.7.1 information. r71si1594233lfe.161 - gsmtp

Нужно в конфиг exim добавить:

# vim /etc/exim/exim.conf

disable_ipv6 = true

Ну или для ipv6 прописать корректную PTR-запись.