Lots of deferred errors all of a sudden

[CdtDelta]

Hey all,
I've had a Zimbra RC2 server (running on Ubuntu 6.06 TLS) going for about a week or so. Everything has been running very smoothly, but today when I got the daily mail report, I saw this in the error section:


2007-11-30 23:16:33 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 11:50:48 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 23:01:47 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 16:30:29 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 16:25:08 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 20:02:21 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 20:28:59 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 21:03:35 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 14:12:00 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 11:42:59 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 11:40:53 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 13:28:44 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 19:55:44 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 17:20:45 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 11:52:26 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 20:43:27 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 12:49:40 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 15:28:06 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 12:58:39 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 22:45:56 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 16:49:52 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 23:14:59 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 12:53:56 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 14:41:44 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 11:49:21 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 13:37:32 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 12:32:31 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 22:36:09 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 22:53:27 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 23:28:02 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 23:33:03 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 21:19:08 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 20:18:36 deferred (connect to zimbra.server[<my public IP>]: Connection refused)
2007-11-30 21:17:38 deferred (connect to zimbra.server[<my public IP>]: Connection refused)

(I've replace the actual hostname and public IP obviously)

Now I'm getting mail, and I'm able to send mail out, but I'm not sure how to troubleshoot this. I'm seeing more messages like this in the zimbra.log today, but it's sporadic. DNS seems to be working fine, I can do an lookup on the zimbra server and it's pointing to the right machine.

Any ideas on where to start looking?

Thanks ahead of time....