main.cf and postconf

[UKenGB]

It is many years since I set up postfix on my Mac server and it's use is now purely for local email, i.e. users on home network. However I have some issues with this and could really do with some help.

First of all, changes I have made in main.cf are not being used. AFAICT I am editing the main.cf that is used:-

ps ax | grep master => master -c /Library/Server/Mail/Config/postfix

So main.cf in that directory is the one being used, but changes to that file are ignored. I'm kinda stuck trying to figure out what appropriate changes to make when I don't know how to actually make any changes to the config being used.

What does 'postconf -d' show?

I know it is supposed to be the 'defaults', but from where is it getting those defaults? Hard coded into the executable? If so, how come myhostname, mydomain and mynetworks all contain data specific to my network.

It is almost as if the configuration being used is an amalgam of main.cf in the above directory and also from /etc/postfix, but I don't believe postfix does that sort of thing.

As I said, many years since I last played with postfix and could do with some assistance.