Error: "554 5.7.1 Rejected message by MTA, RDNS record for connecting IP does not exist"

Products

• Messaging Gateway

Issue/Introduction

You are not getting mail messages to complete in Symantec Messaging Gateway (SMG) due to unavailability of reverse DNS record for an IP address.

554 5.7.1 Rejected message by MTA, RDNS record for connecting IP does not exist

Environment

Messaging Gateway

Cause

The SMG cannot find a reverse DNS lookup for the IP address in question while reverse DNS lookup is enabled.
The owner of that IP address does not have a DNS record with a PTR resource available.

Resolution

The best solution is to have the owner of the IP addresses DNS records add a PTR record to resolve that IP to a fully qualified domain name (FQDN).

You can also disable the check in SMG:

1. Log into the Control Center as admin.
2. Click Protocols.
3. Click Settings.
4. Uncheck 'Reject connections where no reverse DNS record exists for the connecting IP address'.
5. Click Save.

 

Additional Information

Understanding How DNS Validation Works