Network & ports

To join a room you usually don't need to change anything. Ports matter for whoever opens the room, the coordinator.

In short

Port	Protocol	What it is for	Must it be open?
22125	UDP	The room: the other musicians connect here to the coordinator.	Yes, on the coordinating computer. MusicApp tries to open it by itself.
22126	UDP	Your own connection, including direct links with other musicians.	Optional: if closed, audio goes through the coordinator.

The ports are always these two, on every computer: a rule you add on the router keeps working.

1. Automatic opening

MusicApp asks the router to open the ports by itself, with UPnP or NAT-PMP/PCP: there is nothing to switch on. This works on most home routers when these features are enabled. Rules you made by hand on the router are respected.

Audio travels directly between the musicians' computers. Only when two of them cannot reach each other does their audio go through the coordinator, compressed with Opus to keep it light; there is no server in the middle.

On first launch MusicApp measures your line and picks format and buffer by itself. To measure again: «Stanze» (rooms) page → «Rete e formato...» → «Prova la connessione» (test the connection), which also checks whether your room can be reached from the Internet.

2. Opening it on the router

If the test says the room is not reachable:

Find the computer's local address. Mac: System Settings → Network → your connection → Details. Windows: open Command Prompt and type ipconfig, line «IPv4 Address» (e.g. 192.168.1.23).
Open the router page in your browser: usually 192.168.1.1 or 192.168.0.1 (FRITZ!Box: 192.168.178.1). The address and password are often on the label under the router.
Look for «Port forwarding», «Virtual server» or «Port sharing».
Add a rule: protocol UDP, external port 22125, internal port 22125, to the local address from step 1. Optional: the same rule for 22126.
Recommended: give the computer a fixed address in the router («static DHCP», «address reservation») so the rule keeps working.
Go back to MusicApp and run «Prova la connessione» again.

3. Computer firewall

Mac: if macOS asks «Do you want MusicApp to accept incoming network connections?», press Allow. If you said no: System Settings → Network → Firewall → Options, and allow MusicApp.

Windows: on first launch allow MusicApp on private networks. If you denied it: Windows Security → Firewall & network protection → Allow an app through firewall → MusicApp.

4. CGNAT and double NAT

Some providers, especially on fixed wireless, 4G/5G and some budget plans, share one public address among many customers (CGNAT). Then no router rule can open the ports.

MusicApp still tries to open the way: with the help of the online service (which never sees the audio) the computers exchange addresses and open the link from both sides. This works with many providers, not all. The automatic choice of the coordinator also counts who can be reached best. To be sure you can coordinate, ask your provider for a public IPv4 address (sometimes free, sometimes paid).

With two routers in a row (double NAT), open the port on both or set the first one to «bridge» mode.

5. To play better

Use an Ethernet cable: Wi-Fi adds irregular delays.
During rehearsal avoid downloads, updates and streaming on the same line.
On slow connections MusicApp uses Opus instead of PCM: it uses far less bandwidth. You can also choose it yourself, in «Rete e formato...».
Whoever has the best connection is the ideal coordinator: MusicApp picks them by itself, even while you play, without interrupting the audio.

If something goes wrong, the app's «Strumenti» (tools) page has «Diagnostica rete» (network diagnostics) and «Segnala un problema» (report a problem), which prepares an email to support@musicappitaly.com with the technical report.