A small UDP reflector that lets RemSound peers reach each other across the internet without Tailscale in the audio path. Two modes in one binary:

• v1 (pairwise) — the original two-slot reflector. First two endpoints to send a valid RemSound v1 packet claim the slots; their traffic gets mirrored to each other. Used by RemSound clients up to v1.x.
• v2 (lobby) — a multi-peer lobby (default cap: 10) keyed on a per-instance CLIENT_ID. Used by RemSound clients that emit v2 packets. Periodic LobbyRoster packets keep clients informed of who's in.

A single relay instance handles both protocols concurrently on the same UDP port. v1 clients keep working unchanged; v2 clients get the lobby model. (A v1 client and a v2 client cannot hear each other in the same session; that's a deliberate scope cut for this release.)

Tested on Raspberry Pi OS Bookworm and Debian / Ubuntu. Requires python3 and curl (both usually preinstalled).

# 1. Download and extract the latest server tarball.
curl -L -o /tmp/remsound-server.tar.gz \
  https://github.com/Ednunp/RemSound/releases/download/server-v2.0/remsound-server-v2.0.tar.gz
tar xzf /tmp/remsound-server.tar.gz -C /tmp
cd /tmp/remsound-server-v2.0

# 2. Install — sets up the relay AND auto-updates.
sudo ./install.sh

# 3. Open UDP 47830 in the firewall and / or router port-forward.
#    On UFW: sudo ufw allow 47830/udp
#    On UDM / pfSense / etc.: WAN UDP 47830 -> this host's LAN IP.

# 4. Confirm it's alive.
sudo ./smoke-test.sh

After install, the auto-updater is enabled. Future releases roll out automatically — no manual SCP, no manual edit. To pin to the current version:

sudo systemctl disable --now remsound-relay-update.timer

To check for updates manually:

sudo systemctl start remsound-relay-update.service

To uninstall everything cleanly:

cd /tmp/remsound-server-v2.0   # or wherever the bundle is
sudo ./uninstall.sh

• Listens on UDP 47830 (chosen to avoid clashes with RemSound's own defaults — 47820/47821/47822 — plus NetFlow 2055 and NUT 3493).
• Bound to 0.0.0.0, so the kernel routes via the default interface. Tailscale must NOT carry this traffic — the whole point of the relay is to remove Tailscale's hops from the audio path.
• The relay process itself never decodes audio. It validates the RemSound header (magic RMND, version 1 or 2) and forwards or drops.

Structured key=value lines. Notable events:

event=startup version_supported=v1,v2 listen=0.0.0.0:47830 max_clients=10

# v1 (pairwise)
event=peer_joined addr=1.2.3.4:5555 slots_filled=1
event=peer_paired a=1.2.3.4:5555 b=5.6.7.8:9999
event=peer_dropped reason=idle addr=1.2.3.4:5555 remaining=1
event=peer_replaced old=1.2.3.4:5555 new=9.8.7.6:4444

# v2 (lobby)
event=client_joined client_id=<uuid> addr=1.2.3.4:5555 count=2
event=client_endpoint_update client_id=<uuid> old=1.2.3.4:5555 new=1.2.3.4:6666
event=client_named client_id=<uuid> name=Andre
event=client_left client_id=<uuid> addr=... reason=bye
event=client_idle_expired client_id=<uuid> addr=...
event=lobby_full attempted_client_id=<uuid> addr=... count=10 max=10

# once a minute
event=stats forwarded=N dropped_unpaired=N dropped_lobby_full=N
            rejected_bad_header=N pair_changes=N lobby_changes=N
            client_count=N v1_peers=[...] v2_clients=[...]

Never logs CLIENT_ID payload bytes beyond the UUID itself. Never logs audio payload.

The relay is small and (after this release) doesn't change often, but when it does we'd rather not chase every operator to re-SCP. The updater polls GitHub Releases for tags starting with server-, finds the highest version, downloads it, swaps the files, restarts the service, and falls back to the prior version if startup fails. Logs everything to /var/log/remsound-relay-update.log.

It only triggers on server-* tags, so RemSound client releases (v1.x, v2.x without the server- prefix) don't affect the relay.

Either disable the timer:

sudo systemctl disable --now remsound-relay-update.timer

…or run uninstall.sh (removes the updater scaffolding entirely along with the relay).