I use Nethserver for a couple of years ago, And I use DMARC, SPF and DKIM. I think that the user interface is pretty nice to do in a simple way those configurations. Great!! But sometimes you need something more specific.
In my case I need to avoid sign the Subject of my messages.
I can do that using in /etc/opendkim.conf the parameter
OmitHeaders Subject
and it works.
But as the file states at the beggining, that file is overwrite sometimes.
When I had to configure other files I use /etc/e-smith/templates/etc/… and I know that the changes are properly deployed.
But in this case I don’t have a default /etc/e-smith/templates/etc/opendkim/opendkim.conf to change so I have doubts about the right file where I have to add the line.
OmitHeaders Subject
I created a file /etc/e-smith/templates/etc/opendkim/opendkim.conf with only that line and the system doesn’t add it to /etc/opendkim.conf