I am seeing emails from a few domains getting rejected with "517 domain does not exist" messages.
Using dig domain mx and testmxlookup domain shows these domains do not have valid A records for their MX records. However, I know these particular messages are valid and I want to accept them.
Other than setting BOFHCHECKDNS=0, is there some way I can configure Courier to accept mail for these particular domains?
Yes -- tell the sender to fix his DNS.
Sigh. Yes, ideally that would be the way. Unfortunately, it is not an ideal world. Are there any other methods available that are actually within my control?
The previous answer is the correct answer. What is the point of having RFCs if
no one enforces them? If you take the extra few minutes to message the
postmaster at those domains and remind them that MX servers are to have A
records, you may be surprised how quickly the DNS gets fixed. Or you can be lazy
and put that sentence in your reject message, publish your policy online and
that would still give admins enough to fix the problem. And if they still choose
not to follow the RFCs, then their servers don't get to play with yours!
A fair amount of unsolicited commercial email comes from servers that aren't
properly configured to send mail on the Internet. You want to take a bite out of
spam? Enforce the RFCs. If you want to be closer to your "ideal world", you
have to do your part to help in the transition. Otherwise, things change much
Perhaps the lecture is useful to others on the list but you are presuming I have not attempted to contact the admins of the other servers. They made choices. I can not control that. I do hope to control what does get through and these messages are useful to my internal users. Therefore, I am attempting to find a way to get them through without compromising all of the positive effects of the dns checking.
I will try Mr. Sam's suggestion and see if that works.