Solved RT-AX88U (3004.388.11): Client List Bugs and Plex Port Forwarding Issues

[gamesman]

Solved

Router: ASUS RT‑AX88U
Firmware: Asuswrt‑Merlin 3004.388.11

Lately I’ve been experiencing several issues:

1. The connected clients list is incorrect.
   Devices that were connected weeks ago are still shown as currently connected. The list does not update properly, and the only way to fix it is by doing a hard reboot of the router.
2. Port forwarding / UPnP is unreliable for my Plex server.
   The port used by Plex will not stay open, even when port forwarding is configured or UPnP is enabled.
3. AiMesh status does not match the connected clients list.
   In the AiMesh overview, the client list always shows 0 connected devices, even though clients are clearly connected through the mesh nodes. This does not match what is shown in the regular connected devices list.

Has anyone else experienced similar issues with 3004.388.11 on the RT‑AX88U, especially related to client list accuracy, port forwarding stability, or AiMesh reporting?

 

[bennor]

#1 is likely a well known issue. The Network Map client list/status list sometimes just isn't updated correctly, many comments about it over the years.
#2 is also likely a known issue with Plex remote access and the Asus router. When using Plex's remote access feature I had to setup a port forward rule for the remote access port for the Plex Media server. Otherwise the Plex remote access wouldn't work properly. Personally, I always disable UPnP on the router.
#3 is also likely a known issue that I'm not sure much can be done about it since AiMesh is closed source from Asus.

 

[ColinTaylor]

1. Known issue across various Asus routers that dates back years. Nothing Merlin can do about it as this comes from closed source Asus code.

2. How are determining that the port doesn't stay open? Are you using any VPNs?
Try disabling UPnP in Plex and using a manual port forwarding rule (I know you said you'd tried this). Check that the rule still exists when the problem occurs by looking at the router's System Log - Port Forwarding page.

 

[gamesman]

i did a downgrade to 388.7 and port is open. will look in to the pointers mention from you guys

Edit:

I’ve recently updated my RT-AX88U to the latest firmware (3004.388.11) and performed a full factory manual reset to ensure a clean slate. While reconfiguring my network (about 20 static DHCP reservations), I’ve encountered a few quirks I’d like to share/verify with the community.

1. Plex Port Forwarding & TrueNAS SCALEI was struggling with Plex remote access showing "Green" but still being closed when checked via canyouseeme.org.

• The Fix: I moved away from UPnP and set up a manual Port Forward.
• Port Mapping: I mapped external port 32200 to internal port 32400.
• The Solution: What finally stabilized the connection was switching the Plex App in TrueNAS SCALE to "Host Network" mode and disabling UPnP/PCP inside the Plex network settings. This bypassed the internal k3s networking issues that often plague TrueNAS apps. It’s now rock solid.

2. Client List & UI BugsEven after the clean install, the Client List UI feels a bit "clunky." Sometimes devices don't show up immediately after a reboot, or they retain old icons despite being reassigned.

3. AiMesh Wired Backhaul SetupI also noticed that the AiMesh handshake still insists on being wireless-first. I had to pair my nodes wirelessly in the same room before moving them to their permanent locations and plugging in the Ethernet cable. Once connected, I had to manually set "Backhaul Connection Priority" to "1G/2.5G WAN First" to ensure it didn't fail back to wireless.

Question for the experts:Has anyone else noticed issues with WiFi Agile Multiband on this build? I’ve disabled it for now to maintain compatibility with some older IoT devices (2.4GHz), but I'm curious if the implementation has improved in .11.

Also, for those using TrueNAS – do you find manual Port Forwarding to be the only reliable way with the new Asus firmwares, or is anyone actually getting UPnP/NAT-PMP to work consistently?

 

[gamesman]

1. Known issue across various Asus routers that dates back years. Nothing Merlin can do about it as this comes from closed source Asus code.

2. How are determining that the port doesn't stay open? Are you using any VPNs?
Try disabling UPnP in Plex and using a manual port forwarding rule (I know you said you'd tried this). Check that the rule still exists when the problem occurs by looking at the router's System Log - Port Forwarding page.

No vpn. i run my own vpn on the router for my cell phone to conect to

 

[bpsmicro]

Depending on your Plex needs, you may want to look into Tailscale. It's like a point-to-point VPN that allows you access to your Plex from your other machines/tablets/etc without needing to open the port.
Not viable if your Plex server is shared with many people, but if it's just you and select family members, that might be a better choice.

 

[gamesman]

Depending on your Plex needs, you may want to look into Tailscale. It's like a point-to-point VPN that allows you access to your Plex from your other machines/tablets/etc without needing to open the port.
Not viable if your Plex server is shared with many people, but if it's just you and select family members, that might be a better choice.

Thanks for the tip but that wont work for me

 

[killweav]

#2 is also likely a known issue with Plex remote access and the Asus router.

Same. Try avoiding UPnP for security purposes. Also disable Plex relay for more consistent performance, IMO.

 

[gamesman]

Same. Try avoiding UPnP for security purposes. Also disable Plex relay for more consistent performance, IMO.

Thanks for the tip regarding relay. its disable now

 

[Dedel66]

I think a more precise title for this thread would be desirable.
A solved symbol would also be nice.

 

[gamesman]

I think a more precise title for this thread would be desirable.
A solved symbol would also be nice.

Done