Hi list, For my own usage I wrote a new DNS filter which is executed by smtp / lmtp client before executing DNS request.
It allow to force response on MX requests without performing DNS request, or force "domain not found” response. - For example, I can build MX response to force an email to be routed on my own servers in place of the real destination serveur. This is useful for tests. - Other example is an easy way to integrate relay on Internet in front of existing couple of MTA without changing any configuration and keeping the high availability provided by the DNS multiple MX records. (the “relay" transport doesn’t seem to allow multiple target). - Next example is blacklisting specific domain before performing the DNS request. Are you interested by the patch which integrate this functionality in main postfix branch ? Thanks, Thierry
