u/Dangerous_Low_7389

Hi everyone,

I've spent days trying to figure out why my devices never establish a direct connection to each other — only relay via DERP(dfw) — and the most noticeable impact is that watching 4K movies from my self-hosted Jellyfin over Tailscale constantly buffers/stutters (the relay's throughput can't keep up).

Context:
- Ubuntu Server homelab, several devices on the tailnet (Android TV, iPhone, iPad, Windows PC).
- I tested with TWO different network setups: first behind a cheap consumer router, then connected directly to the ISP's modem (Telmex/Mexico). In BOTH cases, the result is identical.

tailscale netcheck in both cases:
- UDP: true
- MappingVariesByDestIP: true (consistent across both routers)
- PortMapping: UPnP (working, confirmed UPnP is active and responding)
- Nearest DERP: Dallas, ~46-62ms

tailscale ping to two different peers (Android TV and iPhone), 10/10 attempts each:
- 100% via DERP(dfw)
- Latencies of 73-171ms
- "direct connection not established" in both cases

Already ruled out: active exit node (none selected), DNS (MagicDNS working fine, no overrides), bandwidth (86Mbps down / 64Mbps up, nothing saturated), AP isolation on the router (disabled), and a saturated UPnP table on the previous router (no longer applies after switching routers).

My current hypothesis is ISP-side CGNAT, since MappingVariesByDestIP stays true regardless of the router, which per your docs is the typical signature of symmetric NAT imposed upstream of my local network.

Questions:

1. Has anyone with Telmex/similar ISPs in Mexico confirmed CGNAT and found a solution other than a Peer Relay?
2. Is it worth setting up a Peer Relay on my VPS (I have one with a public IP) for this, or is there another way to force/improve NAT negotiation?
3. For 4K streaming specifically over DERP, is there any way to prioritize throughput over latency, or is a Peer Relay literally the only way to improve this?

Thanks in advance.

Hi guys, I’m not new to this, but recently on Strong (in the official Tivimate app) the channels cut out every 20 minutes – the screen goes completely black – and I have to switch channels and then switch back to the original one. It doesn’t happen with all channels, but it does with most of them. I’ve already changed the URLs three times, as my provider gave me several different ones, but none of them fixes the problem. I’ve tried on two different devices, using both Ethernet and Wi-Fi, and also with a VPN, but there’s been no change. Please What could I do? Thank you very much in advance

Hi, I’m not sure if this has already been mentioned, but having watched *It* (1 and 2) and *It: Welcome to Derry*, the correct order to watch the series would be: *It: Chapter 2* first > *It: Chapter 1* > *It: Welcome to Derry*. Is that right?

I say this because the series is told from the perspective of ‘It’, which is trying to kill the Losers’ parents in order to prevent its own death, warping time and space to do so.

Or what theories do you have?

I’m using Strong 8K to watch matches in 4K, but sometimes, every now and then, it buffers, so I turned on my VPN (Proton VPN – paid version) but it hasn’t made any difference, and it’s still buffering just as much or even more. I’m connected to my Starlink network, and I’m practically the only one connected. I’m not using an Ethernet connection; I’m on my Starlink’s 5G network. What should I do?

Today I renewed my Strong subscription for another 6 months, but for some reason the channels from Mexico/Latin America were just showing a black screen, so what I did was change the DNS addresses my provider gave me to ones that were CF (without a VPN) Info Here , and I also changed the output format to HLS. For some reason, everything was fixed right away. I was reading a bit here on this subreddit and came to that conclusion—in case anyone else runs into this, give it a try. I don’t use a VPN because it’s not necessary here (due to my country’s laws).