Postfix auto start on Sierra for smtp relay Postfix works great when I start it manually.  Can relay off of it from other hosts on my network; telnet to it on port 25 etc.

How do I get it to auto start such that It will always be listening on port 25?

I understand it starts up every minute or so and sends whatever has been manually written to the queue (like with the mail command) but I want it listening for connections on port 25 (Which it does if I start it manually).

I've found a bunch of things online but can't get any to work (they seem to apply to previous versions of OS X).
To get this working on Sierra you have to modify the existing launch daemon slightly:


Disable SIP
Modify /System/Library/LaunchDaemons/com.apple.postfix.master.plist:

sudo nano /System/Library/LaunchDaemons/com.apple.postfix.master.plist


remove the lines:

&lt;string&gt;-e&lt;/string&gt;
&lt;string&gt;60&lt;/string&gt;


add the lines:

&lt;key&gt;KeepAlive&lt;/key&gt;
&lt;true/&gt;


save the file and exit nano
Reload the launch daemon:

sudo launchctl unload /System/Library/LaunchDaemons/com.apple.postfix.master.plist
sudo launchctl load /System/Library/LaunchDaemons/com.apple.postfix.master.plist

Enable SIP