Using the "ngircd 20.2" IRC server and trying to get access to it via the WAN port I find there is a lack of persistence in port 6667 once enabled.  Mesh network access is rock steady - WAN access is steady only after a weird sequence of steps is followed to make it work. The details below have only been tested on all nodes in 5 mode.

When first setting up the server after going through the adjustments in the docs, then saving and rebooting the router, the IRC server is fully available via the LAN ports, mesh wifi network, and any tunneled connections. IRC is not available via the WAN port. By going through "Setup", "Port Forwarding... Services", "Save Changes" and rebooting the router, that port is still not available at the WAN port and you cannot access the server. There is no presence of port 6667 and I've used a sniffer to verify this. The mesh network can access IRC but nothing on the WAN can.

Now at this point, if I again sign into "Setup" on the mesh status page, then select "Port Forwarding... Services", and click the "Save Changes" button again, but at the same time keep initiating a connect command using an IRC client on the WAN port, at about 15 seconds the client suddenly connects through the WAN port. After that it will stay connected as long as no further changes are made to the router node. The IRC server will remain fully accessible now via the WAN port and any client connected on the WAN port shows up on the list visible to any client connected on the LAN ports on the local mesh, or tunneled mesh connections.

Now if I issue a disconnect command on the WAN port client, it disconnects, but any subsequent attempt to reconnect fails and port 6667 is gone. No further connection via the WAN port is possible.  Clients on the LAN ports and mesh network remain connected just fine. 

From this point on, the only way to get the WAN port client to connect again is to click the "Save Changes" button on the "Port Forwarding... Services" screen and again initiate a connect command to the IRC client connect at the WAN port. Again, at about 15 seconds, port 6667 opens up and allows the client to connect. You then get the same situation as before - the connection is solid as long as nothing is changed in the router. Rebooting kills this connection of course.

"Save Changes" in the Basic Setup screen and rebooting  has no effect and does nothing to save whatever parameters are needed to avoid this sequence. Enabling / disabling / re-enabling the ports does nothing permanent either. Only the "Save Changes" sequence described above opens the WAN port and it will work even with no changes of any kind done to the ports, numbering or port forwarding. I've tested this on several 54G and 54GS units and it works on all of them.

Is it safe to assume this is a "bug" and not a hidden feature of the firewall?

Regards, Wil.