Server Version#: 1.29.2.6364
Player Version#: N/A - Web, Android Mobile, Android TV, Samsung Tizen TV
Over the last week or so, I’ve been experiencing issues accessing Plex via the plex.tv domain. The errors being reported looked like they were DNS related, so I did a little digging to see if I could figure out what was happening. I run Pi Hole on my home network, with network segmentation having my Plex server residing on it’s own VLAN with f/w rules in place to allow traffic to my main LAN and IoT VLAN’s (for things like smart TV’s, Roku’s etc). Historically, there have been no issues whatsoever.
At this point I should point out that the issues have been exclusively isolated to Plex. No other domains or services have been affected and web traffic is normal, as expected. My Pi Hole logs show the following when trying to resolve a plex.tv address in a browser (with the resolver cache cleared, incognito):
This clearly points to the issue being DNS related, specifically it looks to be DNSSEC at play. I use Quad9 for the upstream resolver, which utilises DNSSEC and DNSSEC is enabled on my Pi Hole.
It’s worth noting that I have tested numerous other upstream services such as Google, OpenDNS and Cloudflare, all of which also use DNSSEC. I have also gone through all of my filtering lists and custom blocking rules in Pi Hole and eliminated those as culprits. I even whitelisted all of the domains that Plex uses to see if that would clear things up. The results were the same.
So, I ran a DNSSEC check on the plex.tv domain and it all looks okay, aside from a couple of errors in the tv zone.
Now, I disabled DNSSEC on my Pi Hole, cleared my resolver cache and tried to resolve a plex.tv domain URL in a new incognito browser. It worked just fine, no slow loading, no errors.
I re-tested by enabling DNSSEC again, clearing the resolver cache, and the issue returned immediately, followed by the same errors in my Pi Hole logs.
So, I can only conclude that Plex has issues with their DNSSEC config. This might explain why the issue isn’t viewed as being more widespread as most people are not running a DNS server, like Pi Hole, with DNSSEC enabled.
As I said, the issue has been occurring now for about a week or so and it appears to be somewhat intermittent, albeit regular. Severity varies from slow but successful loading of Plex services on any client type, to outright failure to load.
I’ve seen a couple of scattered threads on Reddit with people experiencing the same, or very similar issues, with Plex but I was wondering if anyone else had noticed the same thing
