Linux Address Already in Use

Overview

Linux "Address already in use" (EADDRINUSE) means another process is already listening on the requested port.

Key Details

• errno 98 — bind() failed because port is occupied
• Common when restarting services quickly
• TIME_WAIT state can also block port reuse
• Only one process can bind to a specific port

Common Causes

• Previous instance of the service still running
• Another service using the same port
• Port in TIME_WAIT state after recent connection
• Zombie process holding the port

Steps

1. 1Find what is using the port: ss -tlnp | grep :port
2. 2Kill the process using the port: kill PID
3. 3Use SO_REUSEADDR socket option in your code
4. 4Wait for TIME_WAIT to expire (usually 60 seconds)

Tags

More in Network

Frequently Asked Questions