We have been evaluating SpamFilter ISP for a few months, and have been waiting for the new budget to be approved so we can purchase two licenses.

Our current configuration is we have SpamFilter running on two seperate machines (one is primary, one is secondary) with MySQL running on the primary server for quarantine purposes.  The secondary server isn't as beefy and it uses the database on the primary server.

SMTP records point to the primary first, then the secondary server.

This weekend we discovered that SpamServer was 'hung' or appeared to have stopped filtering/forwarding mail to our Exchange server.  I sent a test message from gmail to my work mail, and received the following error back:

"This is an automatically generated Delivery Status Notification

Delivery to the following recipient failed permanently:

my e-mail address

Technical details of permanent failure:
PERM_FAILURE: SMTP Error (state 12): 557 The server encountered an error while processing this message. Please retry later."

Typically, our failover system works somewhat well, in that if the primary server should crash, or be powered off, mail will still continue to come in on our secondary server.  However, since this message was rejected - it didn't fail over to our second server (via smtp priority) and it wasn't sent back to be requeued in the originator's mail queue. 

I checked the log file from yesterday, and I don't see any error messages prior to the log not receiving entries. 

Normally if Spamfilter should hang, it wouldn't receive any connections, and wouldn't send back a rejection, but that doesn't appear to be the case here.  If it had stopped receiving connections - I wouldn't have received the 557 rejection code, correct?

Any thoughts on what might have caused this?

Sincerely,

Dave Montgomery