PORT 4001 / TCPInfrastructure & CloudExposure Risk: Medium

Port 4001: IPFS API / etcd Client — IPFS P2P Swarm & CoreOS etcd

Used by IPFS swarm peers and legacy etcd cluster endpoints.

Default Service

IPFS API / etcd Client

Process: ipfs / etcd

Transport Protocol

TCP

IANA Registered Port 4001

Docker Port Flag

-p 4001:4001

Container to Host Mapping

How to Check & Kill Process on Port 4001 (EADDRINUSE Fix)

macOS & Linux (lsof / kill)

# Find process using port 4001
sudo lsof -i :4001

# Instantly kill process on port 4001
lsof -ti:4001 | xargs kill -9

Windows (PowerShell & CMD)

# Find PID listening on port 4001
netstat -ano | findstr :4001

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

Cross-Platform Node.js One-Liner

# Kill port 4001 via npx
npx kill-port 4001

# Or diagnose via Castov CLI
npx castov fix "EADDRINUSE :::4001"

Linux Firewall (UFW) & Connectivity Test

# Test if port 4001 is reachable
nc -zv localhost 4001

# Allow or deny port 4001 in UFW
sudo ufw allow 4001/tcp

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Frequently Asked Questions about Port 4001

What is Port 4001 used for?

Port 4001 is the standard network port for IPFS API / etcd Client (IPFS P2P Swarm & CoreOS etcd) operating over TCP. The typical system daemon or process is ipfs / etcd.

How do I kill a process running on Port 4001 (EADDRINUSE)?

On macOS and Linux, run: lsof -ti:4001 | xargs kill -9 (or npx kill-port 4001). On Windows PowerShell/CMD, run: netstat -ano | findstr :4001 and then taskkill /PID <PID> /F.