Unable to send an email: Our system has detected that this message does not meet IPv6 sending guidelines regarding PTR records

Created:

2016-11-16 13:06:04 UTC

Modified:

2017-04-24 11:02:28 UTC

6

Was this article helpful?


Have more questions?

Submit a request

Unable to send an email: Our system has detected that this message does not meet IPv6 sending guidelines regarding PTR records

Applicable to:

  • Plesk 12.5 for Linux
  • Plesk 11.5 for Linux
  • Plesk 12.0 for Linux
  • Plesk 12.5 for Windows

Symptoms

Plesk server has IPv6 address. When an email message is sent from the server to a Gmail account it fails to deliver.

In /usr/local/psa/var/log/maillog in Linux or in C:\\Program Files (x86)\\Parallels\\Plesk\\Mail Servers\\Mail Enable\\Logging\\SMTP\\SMTP-Debug.log in Windows the following error appears:

ipv6_failed_after_I_sent_the_message./Remote_host_said:_550-5.7.1_[ipv6______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._hg7si388602wjb.61_-_gsmtp/

The email message sender receives following message:

Remote host said: 550-5.7.1 [2a00:14e8:211:2123::2  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. la8si618732wjb.94 - gsmtp

Cause

Gmail Guidelines for IPv6 are not met

Resolution

Verify that the IPv6 address has a PTR-record:

# dig -x 2001:db8:f61:a1ff:0:0:0:80 |grep PTR
;0.8.0.0.0.0.0.0.0.0.0.0.0.0.0.0.f.f.1.a.1.6.f.0.8.b.d.0.1.0.0.2.ip6.arpa. IN PTR example.com

Verify that an answer for PTR record query matches the IP obtained via the forward DNS resolution of the hostname specified in the PTR record:

# dig example.com|grep IN|grep A
203.0.113.2
2001:db8:f61:a1ff:0:0:0:80

In case these conditions are not met, contact your ISP/Hosting provider.

Workaround

On Linux, Postfix can be configured to use only IPv4 addresses:

  1. Check the current protocols:

    [root@server ~]# postconf inet_protocols
    inet_protocols = all
  2. In /etc/postfix/main.cf , replace inet_protocols=all with inet_protocols=ipv4 using a text editor (for example, vi):

    [root@server ~]# grep 'inet_protocols' /etc/postfix/main.cf
    inet_protocols = ipv4
    #inet_protocols = all
  3. Restart Postfix:

    # service postfix restart
  4. Ensure that the configuration is updated:

    [root@server ~]## postconf inet_protocols
    inet_protocols = ipv4
Have more questions? Submit a request
Please sign in to leave a comment.