PORT 465 / TCPEmail & MessagingExposure Risk: Low

Port 465: SMTPS — Authenticated SMTP over Implicit TLS

Modern secure port for email submission by mail clients using implicit TLS encryption.

Default Service

SMTPS

Process: postfix

Transport Protocol

TCP

IANA Registered Port 465

Docker Port Flag

-p 465:465

Container to Host Mapping

How to Check & Kill Process on Port 465 (EADDRINUSE Fix)

macOS & Linux (lsof / kill)

# Find process using port 465
sudo lsof -i :465

# Instantly kill process on port 465
lsof -ti:465 | xargs kill -9

Windows (PowerShell & CMD)

# Find PID listening on port 465
netstat -ano | findstr :465

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

Cross-Platform Node.js One-Liner

# Kill port 465 via npx
npx kill-port 465

# Or diagnose via Castov CLI
npx castov fix "EADDRINUSE :::465"

Linux Firewall (UFW) & Connectivity Test

# Test if port 465 is reachable
nc -zv localhost 465

# Allow or deny port 465 in UFW
sudo ufw allow 465/tcp

Frequently Asked Questions about Port 465

What is Port 465 used for?

Port 465 is the standard network port for SMTPS (Authenticated SMTP over Implicit TLS) operating over TCP. The typical system daemon or process is postfix.

How do I kill a process running on Port 465 (EADDRINUSE)?

On macOS and Linux, run: lsof -ti:465 | xargs kill -9 (or npx kill-port 465). On Windows PowerShell/CMD, run: netstat -ano | findstr :465 and then taskkill /PID <PID> /F.