Why a Direct, 500 Mbit Tailscale Link Only Gave Me 10 Mbit for One Stream(tailscale.com)

The Problem My self-hosted Jellyfin was slow whenever I connected to it from abroad over Tailscale. My ISP upload is about 500 Mbit/s, but streams stuttered and iperf3 over the tunnel only managed ~10 Mbit/s: $ iperf3 -c jellyfin-host [ 5] 0.00-10.00 sec 11.9 MBytes 10.0 Mbit/s It wasn’t a relay or routing issue — tailscale status showed a direct connection (not a DERP relay): $ tailscale status 100.xx.xx.xx jellyfin-host linux active; direct xx.xx.xx.xx:41641 So: direct, low-latency, half a gigabit of upload available — and still only 10 Mbit/s for a single stream.