Quick port scan

Check which ports are open on an IP or domain

Need to check a specific port instead? Try Custom Port Scan →
What is a port scan? Open ports on a server reveal which services are running — a web server, mail server, remote access, and more. This tool attempts real connections to 25 commonly used ports, useful for checking your own server's exposure or diagnosing why a service isn't reachable.
Enter an IP or domain above to get started.

Checks 25 common ports (web, mail, database, remote access and more)

Open and closed

Open means something accepted the connection — a service is listening and reachable from the internet. Closed means the connection was refused or got no answer, usually because nothing is running there or a firewall blocks it.

Ports that should rarely be open to the internet

Put remote access behind a VPN instead of opening these ports directly.

Only scan what you own

Scan your own servers and networks, or ones you have permission to test. Many providers treat unsolicited scans as hostile.

Limits

The scan connects over TCP from Cloudflare’s network, so it shows what the internet sees. Hosts behind Cloudflare’s own proxy can’t be scanned this way — you would be testing Cloudflare, not your server. To test a single port that isn’t in the list, use the custom port scan.