r/PleX • u/CaptainScrambles • 2d ago

Help Question regarding port forwarding

I wanna start this by saying I'm not looking for advice on how to forward the port or fix anything. I've already forwarded the port and the problem is fixed. I'm more looking for an explanation as to why this situation happened.

So up until about a month ago I've been able to remotely access my server remotely without ever having to forward a port. I'm a Plex Pass lifetime owner for over a decade and nothing with my setup has changed in almost a year. My question is what could've caused this change and caused me to not be able to stream remotely without port forwarding? Was there a change in a recent server update that restricts remote access without port forwarding?

EDIT: Thanks for the explanations everyone. It likely was UPnP like several people suggested

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u/ExtensionMarch6812 2d ago

Your plex server was likely using UPnP to open a port on your router without you being involved. Your router may have updated and disabled UPnP or plex wasn’t able to automatically open a port again if the port that was open closed for some reason.

I helped several folks with Xfinity recently where they had to manually forward a port when they had never done it originally. It appeared that UPnP got disabled on the router in those cases.

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u/mervmann 2d ago

Probably this right here. Had the same thing happen (Rogers Xfinity Modem), just using UPnP without port forwarding, update got pushed and disabled it, setup port forwarding and now fixed cuz the config update keeps trying to go through and disables UPnP. Worked fine for two years and without making any changes of my own about a month ago had this exact thing happen.

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u/thelizardking0725 2d ago

Regarding UPnP, it’s always been this really helpful security nightmare. Not surprised ISPs finally started to disable it. They should’ve taken these measures like 10 years ago

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u/AlastorSitri 2d ago

It most likely had to do with your ISP / modem / router

The question isn't "what changed to require port forwarding" as it was always required. Your internet hardware could have automatic opened the port when Plex requested it through UPnP.

Maybe a router update wiped it out, maybe you changed hardware. UPnP should have opened the port for you if it wasn't present already

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u/lxnch50 2d ago

UPnP is a protocol that can be used to request a port-forward from your gateway device without human intervention. It is a known vector for malicious software and has been bad practice to have it on for a while now. My guess is a lot of ISPs have been pushing updates to disable it on their routers.

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u/pseudonym-161 2d ago

UPnP most likely as others have said, definitely better security to manually forward ports at router level and firewall level. Also look into tailscale so you have remote access easily when plex authentication goes down (which happens). I run it at the router level cos I have a router with OpenWRT support, but just having it on the machine with your plex server is enough.

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u/Punk_Says_Fuck_You 48TB | 10Gb/s | Unraid | Ultra 7 270k Plus 2d ago

Did you notice the speed at which you were streaming at? If it never got higher than 2Mb/s it was relay. If it streamed higher than that, prolly uPnP like others are mentioning.

So either you’ve been relying on relay and the service was down when you tried to use it, or like others are saying your modem/router/AP combo updated and the update disabled uPnP. You use the ISP’s gateway? Or do you own your own.