Run it on a public server

Every computer connects to it

The server is on the public internet, so every computer can reach it from whatever network it's on. What you copy goes directly between the two computers when possible; when that fails, it's relayed through the server, still encrypted.

• Signaling, TCP 8787. Every computer stays connected to it to find the others, pair and exchange connection details.
• Direct. Computers on different networks connect directly through NAT hole punching, which works on most home and office networks.
• Relay, UDP 3478 and relay ports. When a direct path fails, the server forwards the traffic, still encrypted and limited by its bandwidth.

Before you start

A cloud VM

Linux on x86_64 or ARM64; the smallest size is enough, as the server uses about 15 MB of RAM. You need root.

A public IP

The VM's own public IP works; a static (elastic) one is best. If it changes, every computer has to be updated.

A way in

ssh, or the web terminal in your provider's console.

VMs in mainland China

Without an ICP filing for the domain, enter the IP in the apps, not the domain; see the questions.

Step 1

Open the ports in the security group

In your cloud provider's console, add these three inbound rules to the VM's security group.

Step 2

Run the install script

Give the script the public IP. It installs the server, registers a systemd service that starts on boot, and prints the address to enter in the apps.

$ sudo ./install.sh 203.0.113.10
▶ Installing the binary to /usr/local/bin
▶ Writing the systemd unit
▶ Writing /etc/copysync/server.env (relay address 203.0.113.10)
▶ Starting
  ✓ Running

Installed: copysync-server 1.6.4
In CopySync on each computer, set Settings → Signaling server to:

    ws://203.0.113.10:8787/signal

  Config     /etc/copysync/server.env
  Logs       journalctl -u copysync-server -f
  Restart    systemctl restart copysync-server
  Uninstall  sudo ./install.sh uninstall

Open in your firewall: TCP 8787 (signaling), UDP 3478 (STUN and TURN), UDP 32768-60999 (relay ports, assigned by the OS)

Step 3

Check that it's reachable

Open http://203.0.113.10:8787/healthz (with your public IP) in a browser on any computer. If you see this line, it works.

{"status":"ok","version":"1.6.4"}

If it doesn't load, see the questions below.

Step 4

Enter the address on each computer

1. Open Settings

   Open CopySync on each computer and go to Settings.

2. Enter the public address

   Under Signaling server, enter ws://203.0.113.10:8787/signal with your public IP and press Return or Enter.

3. Check the status

   When Connection shows a green Connected, you're set. If you haven't paired yet, pair under Devices.

Haven't installed the app yet? See the quick start.

Questions