Open Port Checker

Check if ports are open on any server or IP address. Free — no signup required.

20 free checks remaining this hour

Quick:
Custom port ranges are available with a free account. Sign up to scan up to 100 ports per check.
🔒

Firewall Testing

Verify your firewall rules are working. Check if only the ports you expect are open to the internet.

⚡

Service Verification

Confirm your web server, database, or mail server is reachable on the correct port from outside your network.

🛡

Security Audit

Find unexpected open ports. Exposed databases, admin panels, or debug services are common attack targets.

You might also like

Browse all tools
Network Calculator

CIDR, subnet, supernet, and wildcard masks.
IP Geolocation

GeoIP with ISP, AS, and "check my IP".
Tech Fingerprint

Detect CMS, framework, and 100+ technologies.