How to Fix “Failed to Bind to Port” on a Minecraft Server

Direct answer

Bind error vs. address in use

“Failed to bind to port” is Minecraft’s startup symptom. “Address already in use” specifically proves the OS says another listener owns that address/port; a bad `server-ip` can also cause bind failure without that exact OS message.

Paper lists two common causes: another server/process is already using the port, or server-ip is configured incorrectly. Stop duplicate Java processes, verify the listening port, and normally leave server-ip blank.

Check for another process on the port

On Windows:

netstat -ano | findstr :25565

If a listener already owns that port, identify the PID before ending anything. It may be an old server instance, another game server, a proxy, or a deliberate service.

Check server.properties

server-ip=
server-port=25565

Do not put your public IP into server-ip. The setting controls local interface binding. Leave it empty unless you specifically know which local address the server should bind to.

Running multiple servers on one machine

Targeted diagnosis: Review the exact address and port in the first bind failure line. If server-ip is set to an address not assigned to this host, binding can fail even when the port is free. Leaving server-ip blank is often appropriate for a normal single-homed host.

Each server/proxy process needs its own listening port on the same IP. For example, a Velocity proxy may listen publicly on 25565 while backend servers use different local ports. Do not configure two processes to listen on the same IP:port pair.

Fix and verify: Use ss -ltnp on Linux to check an already-owned TCP port. On managed hosting, use only ports allocated by the host and do not edit unrelated applications to free port 25565.

After changing the port

Update the client address, firewall rule, and router forwarding rule so all three point to the same new port. Restart the server fully and confirm the new listener before testing remotely.

Official references

These references were checked while preparing this fix. Version-specific behavior can change, so use the project documentation for your exact release when a detail differs.

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