PORT 445 / TCPSecurity & RemoteExposure Risk: Critical

Port 445: SMB — Server Message Block (Windows File Sharing)

Provides shared access to files and printers across networks. Never expose Port 445 directly to the public internet.

Default Service

SMB

Process: smbd / System

Transport Protocol

TCP

IANA Registered Port 445

Docker Port Flag

-p 445:445

Container to Host Mapping

How to Check & Kill Process on Port 445 (EADDRINUSE Fix)

macOS & Linux (lsof / kill)

# Find process using port 445
sudo lsof -i :445

# Instantly kill process on port 445
lsof -ti:445 | xargs kill -9

Windows (PowerShell & CMD)

# Find PID listening on port 445
netstat -ano | findstr :445

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

Cross-Platform Node.js One-Liner

# Kill port 445 via npx
npx kill-port 445

# Or diagnose via Castov CLI
npx castov fix "EADDRINUSE :::445"

Linux Firewall (UFW) & Connectivity Test

# Test if port 445 is reachable
nc -zv localhost 445

# Allow or deny port 445 in UFW
sudo ufw allow 445/tcp

Frequently Asked Questions about Port 445

What is Port 445 used for?

Port 445 is the standard network port for SMB (Server Message Block (Windows File Sharing)) operating over TCP. The typical system daemon or process is smbd / System.

How do I kill a process running on Port 445 (EADDRINUSE)?

On macOS and Linux, run: lsof -ti:445 | xargs kill -9 (or npx kill-port 445). On Windows PowerShell/CMD, run: netstat -ano | findstr :445 and then taskkill /PID <PID> /F.

Is it safe to expose Port 445 to the internet?

Port 445 has a Critical security risk profile. Provides shared access to files and printers across networks. Never expose Port 445 directly to the public internet.