Ok, I've moved over the articles.
I don't know where I should connect the following link:
which sends to this https://openwrt.org/docs/guide-user/firewall/firewall_configuration#notes_on_connection_tracking (which is now broken as I moved stuff over)
that is this paragraph
Notes on connection tracking
:!: This is now obsolete since fw3 version 2016-11-29 by this commit
By default, the firewall will disable connection tracking for a zone if no masquerading is enabled. This is achieved by generating NOTRACK firewall rules matching all traffic passing via interfaces referenced by the firewall zone. The purpose of NOTRACK is to speed up routing and save memory by circumventing resource intensive connection tracking in cases where it is not needed. You can check if connection tracking is disabled by issuing iptables -t raw -vnL, it will list all rules, check for NOTRACK target.
:!: NOTRACK will render certain ipables extensions unusable, for example the MASQUERADE target or the state match will not work!
If connection tracking is required, for example by custom rules in /etc/firewall.user, the conntrack option must be enabled in the corresponding zone to disable NOTRACK. It should appear as option conntrack 1 in the right zone in /etc/config/firewall. For further information see http://security.maruhn.com/iptables-tutorial/x4772.html .
Stuff like mwan3 and umurmur say it's important, can you please advise or do the edit yourself about this?
I also moved and modified a little the name and title of the landing pages of your new Firewall section so we don't break all external links pointing to what was the main firewall article.