On Wed, Aug 13, 2014 at 5:55 PM, Timothy Murphy <gayleard at alice.it> wrote: > > > As I see it, the principal task of postfix is to take in email > arriving at port 25, and convey it to one or more destinations. > > In my experience email has been working without problems > for as long as Unix has been running, > long before system administrator exams were invented. That was back when it was safe to assume that those one or more destination wanted to receive anything that showed up on port 25. Or that you could reasonably accept the unwanted data and subsequently send it back to wherever the From: line said it came from. Which was basically never but people used to do it before they knew better. > It is not necessary to understand how the internal combustion engine works > in order to drive a car; and there is no evidence that those who do know > make better drivers. Not a good analogy. Cars have a fairly useful user interface for the decisions drivers need to make. MTA's need to have helper programs hooked into various places that are much less standardized to make some decisions for you. -- Les Mikesell lesmikesell at gmail.com