I have a Domino 6.5.1 server configured to send and receive SMTP mail. Works fine.I am using the DNSBL feature to log/reject inbound spam.
For some reason the sender of a rejected email does not get any explanation why. Just a generic message like this:
Error transferring to mail.company.com; SMTP Protocol Returned a Permanent Error 554 Transaction failed
In the log of my server I can see that the message is rejected because it is listed in a DNS blacklist, so it’s working fine except that the sender doesn’t get any explanation.
I have tried writing something like this in the Custom SMTP error message field:
Your server with IP %s is listed at %s as a potential spam server.
Subject: dnsbl custom rejection message not working
Do all rejected sites see a generic rejection or do you just have a specific example?
I suspect the latter. It is common for sending MTAs to attempt to interpret rejections purely based on the numeric code returned (554 in this case) and to construct their own meaning which is then sent back to the originator - a bit like Microsoft’s insistence on trampling all over 404 errors returned by web sites in a misguided attempt to be helpful.
In short, just because you are sending a custom 554 response does not mean that the sending system will pay any attention to it.
One way to test this would be to enable blocking with one of the spamhaus lists sbl.spamhaus.org or sbl-xbl.spamhaus.org, then run the test documented on this page:
It is under the heading “Testing your SBL Setup”.
The result of that test when it comes back to you should confirm that the custom 554 message is indeed working.
Subject: All get the same generic rejection message
I’m afraid that yes - all get the same message. Actually I have two servers, both running Domino 6.5.1.
Server A is the one that doesn’t return a good rejection message.
Server B is returning a good rejection message.
I have put up a (third) test 6.5.1 Domino server which is accessing the internet through a DHCP-based ADSL connection (listed at dnsbl.sorbs.net as being in a risky IP-range). When this server sends smtp-mail to server B I get a nice rejection message, and when it sends to server A I get the generic one.
Subject: RE: All get the same generic rejection message
I too have the same issue. Used to work, at least I believe it did, back in 6.5.1. We’re on 6.5.3 on the iSeries. Here’s the reply when I peformed the test at spamhaus.org.