When I launch mailcow, I see that it inserts a rule in my INPUT chain of iptables in the first position. Not exactly sure what it does. Is there a documentation on this?
I am asking because I have other iptables rules that drop ip connections from certain countries (geoip blocking using ipset). I would much prefer to drop those IP addresses before anything goes to mailcow.
Thank you in advance for any help/pointers.