Postfix config doesn't change (even after a service restart)

Solution 1:

If you want to get the actual value, you need to use the following command:

$ postconf | grep size

Adding -d option will show you the default values.

I quoted this from man postconf:

-d Print main.cf default parameter settings instead of actual settings. Specify -df to fold long lines for human readability (Postfix 2.9 and later).