Open Port Checker
Test whether a TCP port is reachable on any public host or IP address, and see how long the connection took.
What is a port checker?
Network services listen on numbered TCP ports — web servers on 80 and 443, SSH on 22, databases on ports like 3306 and 5432. A port checker attempts a TCP connection to a given host and port from the outside and tells you whether it succeeded. It's the quickest way to confirm a service is exposed and that no firewall is silently blocking it.
Common ports to test
- 22 — SSH remote access
- 80 / 443 — HTTP and HTTPS web traffic
- 25 / 587 / 465 — outbound and submission SMTP mail
- 3306 / 5432 — MySQL and PostgreSQL databases
- 6379 / 27017 — Redis and MongoDB
How to use it
- 1Enter a hostname or IP address.
- 2Type a port number, or tap one of the common-service presets.
- 3Click Check to attempt a TCP connection from our server.
- 4Read the open/closed result and the measured connection latency.
Frequently asked questions
What does 'open' vs 'closed / filtered' mean?+
Open means our server completed a TCP handshake with that port — something is listening and reachable. Closed/filtered means the connection was refused or timed out, which can be a firewall dropping the packet, no service listening, or the host being unreachable.
Why is my port open locally but closed here?+
This tool tests from the public internet inward. A port can be listening on the server yet blocked by a cloud firewall, security group, or the host's own firewall (ufw/iptables). If it's closed here but works locally, check those layers.
Can I check any port number?+
Yes, any port from 1 to 65535. Use the quick presets for common services like SSH (22), HTTP (80), HTTPS (443) and databases, or type your own.
Do you scan private or internal addresses?+
No. For security we resolve the host and refuse private, loopback, link-local and reserved ranges, so the tool can't be used to probe internal networks.