Wietse Venema put forth on 3/12/2011 9:00 AM: > With Postfix, ALL SMTP DESTINATIONS are subject to MX lookup unless
Thank you for clarifying this Wietse. I don't recall seeing this explicitly stated in postconf 5, but I do recall seeing "use [] to disable MX lookups" in the text of many parameters. Since I rarely use these parameters, I guess I simply never made the proper inference that MX lookups are always performed by default. > the destination is inside []. It would be a major WTF to break that > rule for relayhost. After your explanation I now understand the reason why disabling it with [] is the responsibility of the admin--interface consistency. However, that was not the focus of my question, although my second attempt at asking it was unfortunately worded in a way that led you to believe so. The focus of my question was simply why/if doing MX lookups is ever useful or necessary when one is sending all mail through a relayhost. I'm unable to think of a scenario where it would be needed. If there is such a scenario I'd simply like to learn what it is. This is why I asked my original question, to fill in my knowledge gap here. I've never claimed to be a Postfix or SMTP expert. I have some knowledge and I share it with others when I believe it may be helpful. When I lack knowledge, I ask questions. Please don't get frustrated with me when I ask things that you feel I should already know. If I already knew them I wouldn't ask. Note that I correctly answered the question of this thread. Frank implemented my suggestion and is pleased as punch with the results. It was the follow up suggestion from Andreas of using [] that brought us to the current discussion, prompting my MX lookup question WRT relayhost. -- Stan
