* tv@duh.org (Todd Vierling) [Thu 18 Sep 2003, 14:34 CEST]:
On Thu, 18 Sep 2003, David B Harris wrote:
If they don't accept anything on port 25, either by sending all packets to /dev/null or by responding with SYN+RST ("Connection refused"), MTAs everywhere will consider this a "temporary error." Then the wildcard should have included a MX that points to nowhere, rather than implementing a fake MTA that allows the MAIL FROM and RCPT TO addresses to be transmitted. The record "IN MX 0 ." is commonly used for this purpose.
Postfix just throws a "Malformed name server reply" error and keeps the mail in the queue if you do that. No solution there. The expected behaviour is that mail addressed to recipients at nonexistent domains *bounces* with no delay and, of course, with as little information about the transaction leaked to third parties such as TLD name service operators. -- Niels.