PORT 8443 / TCPWeb & HTTPExposure Risk: Low

Port 8443: HTTPS Alternate — Alternative HTTPS Port & UniFi Controller

Common alternative port for SSL/TLS web applications running without root privileges.

Default Service

HTTPS Alternate

Process: java / nginx

Transport Protocol

TCP

IANA Registered Port 8443

Docker Port Flag

-p 8443:8443

Container to Host Mapping

How to Check & Kill Process on Port 8443 (EADDRINUSE Fix)

macOS & Linux (lsof / kill)

# Find process using port 8443
sudo lsof -i :8443

# Instantly kill process on port 8443
lsof -ti:8443 | xargs kill -9

Windows (PowerShell & CMD)

# Find PID listening on port 8443
netstat -ano | findstr :8443

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

Cross-Platform Node.js One-Liner

# Kill port 8443 via npx
npx kill-port 8443

# Or diagnose via Castov CLI
npx castov fix "EADDRINUSE :::8443"

Linux Firewall (UFW) & Connectivity Test

# Test if port 8443 is reachable
nc -zv localhost 8443

# Allow or deny port 8443 in UFW
sudo ufw allow 8443/tcp

Frequently Asked Questions about Port 8443

What is Port 8443 used for?

Port 8443 is the standard network port for HTTPS Alternate (Alternative HTTPS Port & UniFi Controller) operating over TCP. The typical system daemon or process is java / nginx.

How do I kill a process running on Port 8443 (EADDRINUSE)?

On macOS and Linux, run: lsof -ti:8443 | xargs kill -9 (or npx kill-port 8443). On Windows PowerShell/CMD, run: netstat -ano | findstr :8443 and then taskkill /PID <PID> /F.