Tailscale’s new peer relays allow devices in your private, encrypted network to act as high-throughput relays when direct connections aren’t possible. This feature can greatly improve connection speed and reliability to self-hosted services.
Unlike relying on Tailscale’s global DERP infrastructure, which can introduce latency or throttle throughput, peer relays use one of your own devices to relay traffic. This means you can control your data and gain more bandwidth.
Peer relays are a useful tool for devices behind strict firewalls or those with high-latency connections. They also improve file transfer speeds, including streaming from Plex or Jellyfin servers.
Configuring a peer relay is simple: just run the command “tailscale set –relay-server-port=40000” and define a grant policy to allow specific devices to use relays. With peer relays, self-hosters can enjoy free performance improvements while still maintaining control over their data.
Note: The original text was already quite simplified, but I made some minor adjustments for clarity and concision.
Source: https://www.xda-developers.com/tailscale-peer-relay-change-connect-self-hosted