Incoming Mail Problems
Troubleshooting incoming mail
If you're having trouble receiving mail from outside, you need to find out where the message is failing.
It's often helpful to tail the logfile as you send the message:
tail -f /var/log/zimbra.log
To troubleshoot your firewall, it helps to have an account on a system outside of your network.
For mail to flow inbound, servers on the internet need to connect to your MTA on port 25.
host -t mx domain
Mail is delivered to the MTA, but not to the mailbox
If there is a line in the /var/log/zimbra.log like:
postfix/lmtp ... deferred ... connection refused
There is no connection to port 7025 to perform LMTP delivery.
To test this, telnet from the MTA to the zimbraMailHost on port 7025 by name (not by IP). If this is resolving to an IP address on your Firewall, make sure the port is forwarded on to the zimbraMailHost.