Answer
A remote system issued a MAIL command to GMS with a line that is too long. 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
Undefined
so GMS responded with
Undefined
This problem is most likely to be caused by someone who is attacking your system in an attempt to find a weakness. This attack has been identified by GMS and ignored. To find out why this is being done, contact the owner of the IP address Undefined and ask them.
Sending long lines to mail systems is a common method of probing for weaknesses in those servers.
See Also:
- What is the SMTP MAIL clause?
- What is SMTP Response Code Theory?
- How do I contact the owner of a remote server?
Keywords:MAIL compliance RFC821 RFC2821