Server Version#: 1.23.0.4438 (as of this writing)
Mostly posting for historical and perhaps to help someone else.
Symptom: Certain network devices seem to have packet loss and that packet loss stops when the Plex server is unplugged from the network.
This has been happening for quite some time and I finally took the time to track it down. I have a Universal-Devices ISY9941 for home automation that was experiencing packet loss along with a Raspberry Pi (probably other devices). Essentially it’d drop about 25% of it’s ICMP traffic and would be randomly unresponsive during use. I’m making an incredibly arduous process short here but ultimately turning off Plex DNLA solved the issue. I’m unsure as to how Plex DNLA packets were causing the ISY device issues, but I was seeing TCP resets coming from the Plex server to the ISY (Wireshark packet sniff). I could easily trigger the occurrence by stopping the Plex server, waiting for ARP to settle then starting the PMS. Within 5 seconds I’d start seeing packet loss on the ISY.
The behavior seemed a lot like the behavior experienced by @ihshaikh here:
I had this issue a couple years ago and essentially blocked SSDP broadcasts to port 1900 using the local firewall on my PMS. Issue is back and now somehow DNLA was on.
I also covered this back in 2019 here:
Cheers! (…and thanks to the Plex Team for creating such an amazing product! We use it daily.)
