Open Port Checker

Check whether ports such as 22, 80, 443, 3306 or 25 are open on any domain or IP, from our server.

How do I check if a port is open?

Enter a domain or IP address and the ports to test. Our server tries to open a TCP connection to each port and reports it as open, closed (refused) or filtered (no reply), with the connection time.

Reading the results

Open — a service is listening and reachable from the internet.
Closed (refused) — the host is up but nothing listens on that port.
Filtered — a firewall silently drops the traffic.

Databases (MySQL 3306, PostgreSQL 5432, Redis 6379, MongoDB 27017) and RDP (3389) should almost never be open to the whole internet — restrict them with a firewall.

Frequently asked questions

Is port scanning legal?

Checking a few ports on your own or your client’s servers is normal administration. Do not scan systems you have no permission to test.

Why is port 25 closed on my home connection?

Many internet providers block port 25 to stop spam.

Can I check UDP ports?

No, this tool tests TCP only.