Port 9229 (Node.js inspector)

Node.js debugger (node --inspect).

Registered (user) port, 1024-49151 TCP Development tools Localhost or LAN only

What port 9229 is used for

Node.js debugger (node --inspect).

Security: should port 9229 be open?

Localhost or LAN only. Anyone who can connect to the inspector can run code in your process. Never use --inspect=0.0.0.0 on a reachable host; tunnel it over SSH.

IANA assignment

Port 9229 is in the registered range and has no IANA assignment. The usage above is unofficial but widespread.

Check what is listening on port 9229

Linux: is anything listening on TCP 9229?

sudo ss -tlnp 'sport = :9229'

Linux / macOS: which process owns the port

sudo lsof -nP -i :9229

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':9229 '

Windows (Command Prompt)

netstat -ano | findstr :9229

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 9229 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine

nc -vz -w 5 HOST 9229

From Windows

Test-NetConnection HOST -Port 9229

Block port 9229 in the firewall

ufw

sudo ufw deny 9229/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 9229 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 9229 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 9229' -Direction Inbound -Protocol TCP -LocalPort 9229 -Action Block

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Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.