ASUS AC routers won’t port forward

[eibgrad]

Another super late bump to this post, but did this ever gets resolved? I am once again having the same issue on an Asus router (AX68U) and I am unable to port forward at all. The ports are forwarded fine on the old router. Getting the same IP from the ISP, not CGNAT, port forwards are listed fine in the System Log section. Tried everything.

Might be worth dumping the firewall just to verify it's configured correctly. You never know, it might be corrupted for some reason.

iptables -t nat -vnL
iptables -vnL

We can also tell from the dump if the port forward rules are even being hit.

Also, CTF is known to cause lots of things on the router to stop working, including QoS, port forwarding, NAT loopback, among others. It's basically a hack to get more performance out of the router than would normally be possible. But I don't see anything in the GUI that specifically allow you to turn it OFF (I assume it's ON by default). But sometimes the developers know of specific problems and will turn it OFF if you enable certain features, typically QoS. So I would try turning QoS ON to see if that causes CTF to be disabled, and perhaps port forwarding will now work.