PORT 9090 / TCPInfrastructure & CloudExposure Risk: Medium

Port 9090: Prometheus / Cockpit — Prometheus Metrics Server & Linux Cockpit Web UI

Default port for Prometheus time-series monitoring and Red Hat/Ubuntu Cockpit server manager.

Default Service

Prometheus / Cockpit

Process: prometheus

Transport Protocol

TCP

IANA Registered Port 9090

Docker Port Flag

-p 9090:9090

Container to Host Mapping

How to Check & Kill Process on Port 9090 (EADDRINUSE Fix)

macOS & Linux (lsof / kill)

# Find process using port 9090
sudo lsof -i :9090

# Instantly kill process on port 9090
lsof -ti:9090 | xargs kill -9

Windows (PowerShell & CMD)

# Find PID listening on port 9090
netstat -ano | findstr :9090

# Force kill by PID
taskkill /PID <PID_NUMBER> /F

Cross-Platform Node.js One-Liner

# Kill port 9090 via npx
npx kill-port 9090

# Or diagnose via Castov CLI
npx castov fix "EADDRINUSE :::9090"

Linux Firewall (UFW) & Connectivity Test

# Test if port 9090 is reachable
nc -zv localhost 9090

# Allow or deny port 9090 in UFW
sudo ufw allow 9090/tcp

Frequently Asked Questions about Port 9090

What is Port 9090 used for?

Port 9090 is the standard network port for Prometheus / Cockpit (Prometheus Metrics Server & Linux Cockpit Web UI) operating over TCP. The typical system daemon or process is prometheus.

How do I kill a process running on Port 9090 (EADDRINUSE)?

On macOS and Linux, run: lsof -ti:9090 | xargs kill -9 (or npx kill-port 9090). On Windows PowerShell/CMD, run: netstat -ano | findstr :9090 and then taskkill /PID <PID> /F.