After installing the new mailserver, I configured and started using opendmarc as yet another measure to stop the ever increasing amount of spam.
I currently have 3 smtp-milters on my setup: DKIM, Spamassassin and DMARC. After a while my wife was complaining that she did not receive expected emails from certain providers. After doing som grepping in the maillog (cat mail.log | grep opendmarc | grep -v 'socket\|Auth\|localhost' | grep 'fail') I found that quite a lot of the norwegian providers did not have DMARC set up.
So I tried to whitelist them using DomainWhitelistFile and DomainWhitelist. But as there was a very lacking documentation on these, and I could not find anything about the format on the list, I gave it up, and just used IgnoreMailFrom. This way you can just have a comma-separated list of domains you just ignore. It's not a preferable solution, but I had to do it because of still having enough WAF.
There is a website dedicated to list providers in Norway that does not have proper DMARC setup: DMARC-status.