At 08:10 29-03-2008, Henning Schulzrinne wrote: >One of the problems I have seen first-hand is "disappearing" mail. >Example: A webserver sends outbound email directly, but doesn't want >to receive inbound email. The hostname leaks and mail gets sent to >that address, based on the A(AAA) record. The mail is "received", but >disappears into some never-seen /var file. In that case, the sender >never suspects that anything is amiss; it would be much better if the >sender got an immediate "sorry, that domain name doesn't support email >service" error. I came across a few (IPv4) cases where mail and web services are hosted by different organizations. The MX query failed and the SMTP client did a fallback to the A RR. The mail was accepted by the host running the web service and it "disappeared". The above can happen when sendmail is running on the web server and it automatically adds the domain to the list of domains for local delivery and there's a catchall address. Regards, -sm _______________________________________________ IETF mailing list IETF@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf