Answer
A remote system has continued to request recipients for this email message even though the recipients are not acceptable so GMS has rejected the message. This helps to
- prevent your system being "probed" by people who want to discover what your email accounts are called;
- stop spammers from delivering too many messages in one batch;
- prevent tar-pitting where a remote server connects to GMS in order to hold a connection open simply to prevent you getting email; and
- prevent clients, customers or users CCing or BCCing too many accounts with each email message.
The Internet Standard RFCs recommend that up to 100 recipients be allowed for each email address. In practice a value of five to 10 is usually sufficent.
In this case session Undefined was processing a connection from the server/client at Undefined processing a message apparently from Undefined when it received the command
Undefined
so GMS responded with
Undefined Undefined
To date Undefined RCPT commands have been issued and the maximum number allowed is #p8#.
If you wish to allow more recipients, the maximum number of receipts can be increased.
If a remote server or client is issuing the RCPTs, it is recommended that you contact the owner of the system and investigate why they need to copy the message to so many people at once.
See Also:
- What is the SMTP MAIL clause?
- How do I contact the owner of a client?
- How do I contact the owner of a remote server?
- What is SMTP Response Code Theory?
Keywords:MAIL RCPT recipient anti-spam RFC821 RFC2821 tar-pitting