Answer
A remote system or client has connected to GMS in order to send an email message. GMS Anti-Spam carried out a DNS based Black List check and discovered that the remote system is listed as one that should not be alllowed to send email to GMS. GMS has sent an error message to the remote server and shut down the connection.
In this case, session Undefined received a connection from the IP address Undefined and responded with the message
Undefined
If you wish to receive email from this address, you will need to either
- contact the owner of the remote system and ask them to remove themselves from the DNSBL list; or
- switch of the DNSBL check.
See Also:
- How do I contact the owner of a remote server?
- Why has SMTP stopped responding or gone slow?
- What is ORDB?
- Does DNSBL work on version 7A?
- How do I white list certain IP’s so that they pass my DNSBL checks?
- What is SMTP Response Code Theory?
- How do I set up GMS to use the RBL+ database from mail-abuse.org?
- What is the difference between DNSBL check on connect and Mail Clause
- Which servers should I use for DNSBL checks
- What happens if a DNSBL Server does not respond?
- Does the DNSBL try to access the DNSBLs directly or do they go through the DNS?
Keywords:DNSBL anti-spam AS Realtime Blackhole