Cannot connect to server on local network

Plex Players Desktop Players
,
1

Server Version#: 1.21.3.4021
Player M edia Player Version#:4.29.2
Plex for Windows Version 1.27.2.1599-7689068b

I have a new Windows 10 machine that cannot connect to my Plex Media Server running on a Windows 7 system locally. I have checked all my IP settings and can resolve the hostnames and successfully ping in both directions but it will never connect over the LAN. If I have both systems connected to my hotspot, its works. The problem is I do not have high speed internet where I live and will rely on the LAN to stream from my media server.

On the Windows 10 system, if I use Chrome and just navigate to the http://media_server_ip:32400/web it works (only after adding the network to the allowed unauth list). Unfortunately both the Plex Media Player and Plex for Windows app will not connect over the LAN.

Also, my iPhone will stream over the LAN just fine and my children’s Kindle Fires also. Its just a new Windows 10 system.

Any ideas?

2

  1. Make sure that your local network is using a “private” IP range: Private network - Wikipedia

  2. https://support.plex.tv/articles/206225077-how-to-use-secure-server-connections#toc-4

3

My network is private. I am using the router’s default 192.168.1.0 subnet and I cannot see any advanced DNS settings in my router. Just DNS server IP addresses.

What is the Plex Media Player app and/or Plex for Windows using to find the Media Server on my network? Does it use the hostname and DNS resolution or something else?

If the router was the problem I wouldn’t expect my iPhone to work on the LAN which it does without issue.

4

It defaults to “secure connections”. Which means it must use the FQDN of your server. Which means it uses DNS (because you cannot bind a certificate to an IP address). This is all explained in the second link above.
And if your router is performing DNS rebinding protection, it can throw a spanner in the works there.

The mobile apps contain a workaround for the DNS rebinding issue, that’s why they still work.

5

I just update my router’s firmware and still have no advanced DNS options to work around this DNS Rebinding issue, if that is truly the problem. I don’t see anything helpful in the Plex logs, but I could provide them here if you think that would be useful?

Do the apps use a different port that 32400?

6

I ran nmap from the Windows 10 pc and against my server and got the following results:

32400/tcp open plex?
| fingerprint-strings:
| GetRequest:
| HTTP/1.1 200 OK
| X-Plex-Protocol: 1.0
| Content-Type: text/xml;charset=utf-8
| Content-Length: 5282
| Connection: close
| Cache-Control: no-cache
| Date: Wed, 17 Feb 2021 18:20:03 GMT
| <?xml version="1.0" encoding="UTF-8"?>
| <MediaContainer size=“24” allowCameraUpload=“1” allowChannelAccess=“1” allowMediaDeletion=“1” allowSharing=“1” allowSync=“0”
allowTuners=“1” backgroundProcessing=“1” certificate=“1” companionProxy=“1” diagnostics=“logs,databases,streaminglogs” eventStream=“1”
friendlyName=“Dennis-PC” games=“1” hubSearch=“1” itemClusters=“1” livetv=“7” machineIdentifier=“34fad48495341cdfbaa17488615cd0a436c03d74”
mediaProviders=“1” multiuser=“1” myPlex=“1” myPlexMappingState=“mapped” myPlexSigninState=“ok” myPlexSubscription=“0”
myPlexUsername="myemail@gmail.com" offlineTranscode=“1” ownerFeatures="044a1fac-6b55-47d0-9933-25a035709432,04d7d794-b76c-49ef-9184-
52f8f1f501ee,06d14b9e-2af8
| HTTPOptions, RTSPRequest:
| HTTP/1.1 404 Not Found
| X-Plex-Protocol: 1.0
| Content-Length: 85
| Content-Type: text/html
| Connection: close
| Cache-Control: no-cache
| Date: Wed, 17 Feb 2021 18:20:03 GMT
| Not Found

404 Not Found


| Help:
| HTTP/1.1 400 Bad Request
| X-Plex-Protocol: 1.0
| Content-Length: 89
| Content-Type: text/html
| Connection: close
| Cache-Control: no-cache
| Date: Wed, 17 Feb 2021 18:20:03 GMT
|_ Bad Request

400 Bad Request


1 service unrecognized despite returning data. If you know the service/version, please submit the following fingerprint at
Nmap Fingerprint Submitter 2.0 :
SF-Port32400-TCP:V=7.91%I=7%D=2/17%Time=602D5E36%P=i686-pc-windows-windows
SF:%r(GetRequest,1558,"HTTP/1.1\x20200\x20OK\r\nX-Plex-Protocol:\x201.0
SF:r\nContent-Type:\x20text/xml;charset=utf-8\r\nContent-Length:\x205282\r
SF:\nConnection:\x20close\r\nCache-Control:\x20no-cache\r\nDate:\x20Wed,\x
SF:2017\x20Feb\x202021\x2018:20:03\x20GMT\r\n\r\n<?xml\x20version=“1.0
SF:”\x20encoding=“UTF-8”?>\n<MediaContainer\x20size=“24”\x20allowCame
SF:raUpload=“1”\x20allowChannelAccess=“1”\x20allowMediaDeletion=“1”
SF:x20allowSharing=“1”\x20allowSync=“0”\x20allowTuners=“1”\x20backgr
SF:oundProcessing=“1”\x20certificate=“1”\x20companionProxy=“1”\x20di
SF:agnostics=“logs,databases,streaminglogs”\x20eventStream=“1”\x20frie
SF:ndlyName=“Dennis-PC”\x20games=“1”\x20hubSearch=“1”\x20itemCluster
SF:s=“1”\x20livetv=“7”\x20machineIdentifier=“34fad48495341cdfbaa17488
SF:615cd0a436c03d74”\x20mediaProviders=“1”\x20multiuser=“1”\x20myPlex
SF:=“1”\x20myPlexMappingState=“mapped”\x20myPlexSigninState=“ok”\x20
SF:myPlexSubscription=“0”\x20myPlexUsername=“myemail@gmail.com”
SF:x20offlineTranscode=“1”\x20ownerFeatures=“044a1fac-6b55-47d0-9933-25
SF:a035709432,04d7d794-b76c-49ef-9184-52f8f1f501ee,06d14b9e-2af8”)%r(HTTPO
SF:ptions,103,“HTTP/1.1\x20404\x20Not\x20Found\r\nX-Plex-Protocol:\x201.
SF:0\r\nContent-Length:\x2085\r\nContent-Type:\x20text/html\r\nConnection:
SF:\x20close\r\nCache-Control:\x20no-cache\r\nDate:\x20Wed,\x2017\x20Feb\x
SF:202021\x2018:20:03\x20GMT\r\n\r\nNot\x20Found</title
SF:>

404\x20Not\x20Found

”)%r(RTSPReques
SF:t,103,“HTTP/1.1\x20404\x20Not\x20Found\r\nX-Plex-Protocol:\x201.0\r\n
SF:Content-Length:\x2085\r\nContent-Type:\x20text/html\r\nConnection:\x20c
SF:lose\r\nCache-Control:\x20no-cache\r\nDate:\x20Wed,\x2017\x20Feb\x20202
SF:1\x2018:20:03\x20GMT\r\n\r\nNot\x20Found</he
SF:ad>

404\x20Not\x20Found

”)%r(Help,109,“HTTP/
SF:1.1\x20400\x20Bad\x20Request\r\nX-Plex-Protocol:\x201.0\r\nContent-Le
SF:ngth:\x2089\r\nContent-Type:\x20text/html\r\nConnection:\x20close\r\nCa
SF:che-Control:\x20no-cache\r\nDate:\x20Wed,\x2017\x20Feb\x202021\x2018:20
SF::03\x20GMT\r\n\r\nBad\x20Request

400\x20Bad\x20Request

”);

7

I very much doubt that nmap can help you.

Set “Secure Connections” to ‘preferred’ instead of ‘required’ in
Settings - Server - Network

Inspect your Plex client preferences, if it has one regarding secure connections. Set it to “allow unsecure” in the local network.
Some client types even allow you to prefer unsecure connections in the local network.
This should enable the app to fall back to using the local IP address of the server, instead of its FQDN.

8

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