Client host rejected: cannot find your reverse hostname

Symptoms

• Mails are not sent to some addresses.

• There are the following error messages in the /var/log/maillog file:

  CONFIG_TEXT: ME-I0009: [09542A9613144EE695DD7835AC43FDD8.MAI] Remote server has closed connection after 0 milliseconds. Server Response: (-)
  ME-E0059: [09542A9613144EE695DD7835AC43FDD8.MAI] Message Delivery Failure. Attempt (23): Domain (yahoo.com) returned temporary error for email. Message has been requeued.
  ME-IXXXX: [0A9BDE4490704C08A66604721DC0C96B.MAI] Remote server returned a response indicating a temporary failure. Server Response: (450 4.7.1 Client host rejected: cannot find your reverse hostname, [1.2.3.4])

  OR

  CONFIG_TEXT: Reason: Remote SMTP Server Returned: 550 5.7.0 Your server IP address [1.2.3.4] is missing a reverse DNS entry

Cause

Reverse DNS zone for the affected IP address and domain does not exist.

Resolution

1. Check if reverse DNS zone control is delegated to your organization.

2. If zone control is not delegated please contact your IP address provider and request to create reverse DNS zone for affected IP address and domain.

3. If zone control is delegated to your organization create reverse DNS zone for affected IP address and domain.

Reverse DNS zone can be created through Plesk UI (in this case subnet masks 8, 16 and 24 are only available) or manually by creating BIND configuration file:

How to configure PTR record in Plesk