Answer
A remote system issued a VRFY command to GMS containing an invalid email address. GMS has a large number of rules for converting mal-formed strings into a correct email address. The corrected address is then passed on to the subsequent messaging server so that they have no problems with the message. Unfortunately the one presented by the remote server or client has defeated GMS’s ability to correct it, so GMS 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
504 Could not interpret address
This problem is most likely to be caused by someone who is attacking your system in an attempt to find a weakness. This potential 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. Configuring GMS to not respond to VRFY commands is recommended to help keep email addresses on your system private and secure.
See Also:
- How do I contact the owner of a remote server?
- What is the SMTP VRFY clause?
- What is SMTP Response Code Theory?
- How do alerts work?
- How do I contact the owner of a client?
Keywords:VRFY bad email address attack interpret 8109