Thursday, January 4, 2024

Mail Rule unintended results

 My client asked me to help with the following problem: He registered a new user with email address "bswann@example.com". (Yes, this is a fictitious name for illustration purposes.) Internal mail was routing to this new user just fine. But mail arriving from outside the domain was being returned to sender "for policy reasons". At first I thought the message was being rejected by the Barracuda device sitting in front of the Domino mail server. But, no. Then I increased the mail routing logging level, whereupon I could see that the Domino server was doing the rejections.

While working on this problem, I sent a test message that was addressed to bswann@example.com with cc to jdoaks@example.com. (I wanted my client, Joe Doaks (yes, fictitious), to see that I was working on his problem. To my surprise, the mail server rejected both copies of the message this time.

Upon searching the Domino Directory, I found this rule:

IF the To field contains "ann@example.com", THEN reject the message. 

The rule had been created seven year ago. I disabled it. I sent another test message and (Ta Da!) the test message was delivered! It turns out that "bswann@example.com" contains "ann@example.com". 

Then I re-wrote the rule as follows, enabled it, and tested again:

IF the To field IS "ann@example.com", THEN reject the message.

And, yeah, the next test message was delivered just fine. 

Happy New Year. 

Rob