EADDRINUSE - Address already in use

root@linuxfix:~/eaddrinuse$

EADDRINUSE

Address already in use

Solutions

Prerequisites: Start by updating your system to resolve common issues and ensure the solutions provided below are compatible with your current environment.

check_latest_version && sudo apt update && sudo apt upgrade -y

Find process using port

Identify what is using the port:

sudo netstat -tulpn | grep :port

sudo ss -tulpn | grep :port

sudo lsof -i :port

Kill process on port

Terminate the process using the port:

sudo kill -9 process_id

sudo pkill -f process_name

sudo fuser -k port/tcp

Use different port

Start service on alternative port:

service --port 8081

python -m http.server 8080

nginx -c config_with_different_port

Enable socket reuse

Configure socket options:

echo 1 > /proc/sys/net/ipv4/tcp_tw_reuse

sysctl net.ipv4.tcp_tw_reuse=1

What is EADDRINUSE?

EADDRINUSE occurs when trying to bind to a network address (IP:port) that is already in use.

Common scenarios: Starting servers on busy ports, multiple instances of same service, or ports in TIME_WAIT state.

Common Causes

Port already bound by another process
Previous connection in TIME_WAIT state
Multiple instances of same service
Socket not properly closed
Firewall or proxy using port

Debugging Tips

netstat -an | grep TIME_WAIT

ss -s

cat /proc/net/tcp

iptables -L -n

Prevention

Properly close sockets
Use unique ports for services
Configure socket reuse options
Monitor port usage

Additional Resources

Linux Network Configuration

Network configuration and troubleshooting

errno network socket port