- Plesk for Linux
- Postfix with SPF is used.
If send emails to multiple recipients, a lot of the following lines can be found in email headers:
Received-SPF: pass (100.example.com: localhost is always allowed.) client-ip=::1; email@example.com; helo=localhost.localdomain;
Also, the following messages can be found:
552 5.7.0 Number of 'Received:' DATA headers exceeds maximum permitted (in reply to end of DATA command)
This is Plesk bug with ID PPPM-3456 which is planned to be fixed in future Plesk updates.
Currently, there is no workaround.