Port 9222 (Chrome DevTools remote debugging)

Chrome/Chromium --remote-debugging-port, used by Puppeteer, Playwright and headless browsers.

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

What port 9222 is used for

Chrome/Chromium --remote-debugging-port, used by Puppeteer, Playwright and headless browsers.

Localhost or LAN only. The DevTools protocol gives full control of the browser, including cookies and files; never bind it to a public interface.

Service nameProtoDescriptionAssigneeReference

teamcoherence TCP QSC Team Coherence Ewan McNab -

teamcoherence UDP QSC Team Coherence Ewan McNab -

Registry dates for this port: registered 2004-11.

Linux: is anything listening on TCP 9222?

sudo ss -tlnp 'sport = :9222'

Linux / macOS: which process owns the port

sudo lsof -nP -i :9222

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':9222 '

Windows (Command Prompt)

netstat -ano | findstr :9222

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 9222 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 9222

From Windows

Test-NetConnection HOST -Port 9222

ufw

sudo ufw deny 9222/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 9222 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 9222 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 9222' -Direction Inbound -Protocol TCP -LocalPort 9222 -Action Block

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