Open Port Checker
Free ToolCheck if a specific TCP port is open, closed, or filtered on your IP address, server, or firewall.
Instant 0ms
100% Client-Side
Test Remote Port Connectivity
Common ports:
Response Time
Frequently Asked Questions
An open port is a TCP/UDP port configured to accept incoming network packets. Network services (like HTTP on port 80) listen on these ports.
Yes, testing single ports against your own domains and authorized infrastructure is a standard diagnostic check.