Answer
A remote system or client has connected to GMS in order to send an email message. GMS Anti-Spam has checked the name that the system is claiming to be and compared it with the actual IP address of the server that connected. Since these details do not match, GMS sent an error message to the remote server and disconnected from it.
In this case, session Undefined received a connection from the IP address Undefined which issued the HELO command:
Undefined
GMS rejected the connection with the response
Undefined
To resolve this issue, you will need to change the rule for verifying hostnames. These parameters are held in the global variables "VerifyHostname" and "VerifyHostnameMes". These can be set from the GMS Anti-Spam > Identity > Machine Name page in the GUI.
There are many mail servers on the Internet that have mis configured reverse lookups in DNS, to ensure that you do not mistakenly block mail from a legitimate server you may wish to select the option "Use raw IP address in logs", this will ensure that you record the correct IP of the connecting server while not refusing any potentially legitimate connections.
See Also:
- What is the SMTP HELO/EHLO clause?
- My server is failing reverse lookups by remote hosts
- How do I contact the owner of a remote server?
- What is SMTP Response Code Theory?
Keywords:anti-spam AS rejected verifyhostname verifyhostnamemes reverse lookup machine name