A remote system issued a HELO greeting command to GMS with a host name that is too long so GMS has rejected the command.
In this case session Undefined was processing a connection from the server/client at Undefined when it received the command
so GMS responded with
This problem is caused by a remote system which is either
- configured incorrectly; or
- attempting to gain control of your server (by hacking).
In order to resolve this issue you will need to contact the owner of the server or client at Undefined and ask them to correct their software or stop attacking your system. It may also be a good idea to suggest that they install a messaging server/client which implements Enhanced SMTP so that they can benefit from lower bandwidth and latency message transfers.
The operation of GMS will not be affected by this issue.
- What is the SMTP HELO/EHLO clause?
- How do I contact the owner of a remote server?
- What is SMTP Response Code Theory?
- How do I contact the owner of a client?
- What are the benefits of Enhanced SMTP?
Keywords:HELO EHLO compliance hostname RFC821 RFC2821