Free Open Port Checker
Test if a TCP port is reachable on any public host — instant results, no install.
Domain or public IP. Pasted URLs and ports are stripped automatically.
Checking port…
Usually finishes in a few seconds
You've reached the free hourly limit
Log in to keep checking — registered users get a higher hourly quota.
Log in to continueChecked :
TCP handshake probe · 3s timeout · Results cached for 60 seconds
Enter a host and a port and we'll attempt a real TCP handshake from our server. You see in seconds whether the port is open, closed, or filtered by a firewall — no nmap, no command line.
Features
- Any port, 1–65535 - Check well-known services (22, 80, 443, 3306) or your own custom ports.
- Three-state result - Open (handshake completed), closed (host refused), or filtered (firewall dropped the packet).
- Latency reporting - When a port is open we report the connect time in milliseconds.
- IPv4 and IPv6 - We resolve via the system resolver and probe whichever address the host advertises.
- Safe by default - Reserved, private, and loopback addresses are blocked to prevent abuse.
- 100% Free - No account required for limited use.
Tip: A filtered result means a firewall is silently dropping the connection — different from closed, where the host actively refused it. If a service should be reachable but shows filtered, check your firewall or security group rules.