Remote Access keeps dropping out

[dgwharrison]

Server Version#: 1.16.6.1592 running in binhex-plexpass docker on UnRaid 6.7.2

I’ve had plex for years with different routers and installed on bare metal systems and so on. Currently I run a Mikrotik router which has UPNP disabled but I’ve manually mapped port 32400 manually though to the plex docker.

The problem is it keeps dropping out. So if I go to the Settings > Remote Access page it will show me “Not available outside your network” per screenshot:

Then if I press retry I get 'connecting to server (as you’d expect):

Then it will be connected just fine:

But, give it as little as a minute and it will drop out again.

All remotely connecting devices almost always get ‘plex server unavailable’ most of the time. If you persist the connection comes live again but it’s a right pain in the backside.

Presumably it’s a websocket that gets dropped. How would I go about fixing this?

[Achilles]

Have you confirmed that TCP port 32400 is truly accessible from the internet?

[Achilles]

You likely have DNS Rebind Protection enabled on your router.

https://support.plex.tv/articles/206225077-how-to-use-secure-server-connections/

DNS Rebinding

Some routers or modems have a feature known as “DNS rebinding protection”, some implementations of which can prevent an app from being able to connect to a Plex Media Server securely on the local network. For most users, this won’t be an issue, but some users of higher-end routers (or those provided by some ISPs) may run into problems.

Similarly, some DNS providers (including some ISPs) may have this feature.

DNS rebinding protection is meant as a security feature, to protect insecurely-designed devices on the local network against attacks. It provides no benefit for devices that are designed and configured correctly.

Take a look at the following website for an example of how to bypass that for Plex on Mikrotik routers:

https://cewood.xyz/post/mikrotik-dns-rebind-plex/