PORT 993 / TCPEmail & MessagingExposure Risk: Low

Port 993: IMAPS — IMAP over TLS/SSL

Secure encrypted email retrieval and folder synchronization.

Default Service

IMAPS

Process: dovecot

Transport Protocol

TCP

IANA Registered Port 993

Docker Port Flag

-p 993:993

Container to Host Mapping

How to Check & Kill Process on Port 993 (EADDRINUSE Fix)

macOS & Linux (lsof / kill)

# Find process using port 993
sudo lsof -i :993

# Instantly kill process on port 993
lsof -ti:993 | xargs kill -9

Windows (PowerShell & CMD)

# Find PID listening on port 993
netstat -ano | findstr :993

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

Cross-Platform Node.js One-Liner

# Kill port 993 via npx
npx kill-port 993

# Or diagnose via Castov CLI
npx castov fix "EADDRINUSE :::993"

Linux Firewall (UFW) & Connectivity Test

# Test if port 993 is reachable
nc -zv localhost 993

# Allow or deny port 993 in UFW
sudo ufw allow 993/tcp

Frequently Asked Questions about Port 993

What is Port 993 used for?

Port 993 is the standard network port for IMAPS (IMAP over TLS/SSL) operating over TCP. The typical system daemon or process is dovecot.

How do I kill a process running on Port 993 (EADDRINUSE)?

On macOS and Linux, run: lsof -ti:993 | xargs kill -9 (or npx kill-port 993). On Windows PowerShell/CMD, run: netstat -ano | findstr :993 and then taskkill /PID <PID> /F.

Is it safe to expose Port 993 to the internet?

Port 993 has a Low security risk profile. Secure encrypted email retrieval and folder synchronization.

Other Common Network Ports