NETWORK UTILITY

Port Checker

Test one public TCP port at a time for a system you own or are authorized to check.

TCP Port CheckerSingle public target

Check one TCP port on a public target

This utility attempts a single outbound TCP connection from the IP-Lookup.com web server to the public host and port you specify. It is intended for checking services you own or are authorized to test.

Not a port scanner. The endpoint accepts one port per request and blocks private/reserved destination IPs. Do not use it to probe systems without permission.

How to interpret the result

An “open” result means the server completed a TCP connection during the short timeout. A closed/unreachable result can mean the service is closed, filtered, rate limited, unreachable from this server, or simply did not answer before timeout.

What an open TCP result means

An open result means the IP-Lookup.com server completed a TCP connection to the selected public target and port within the timeout. It does not verify the application protocol, authentication state or security of the service behind that port.

Why a closed result can be ambiguous

The service may genuinely be closed, a firewall may silently drop the connection, the target may rate-limit the checking server, or the route may be temporarily unavailable. A single remote test therefore shows reachability from this server, not from every network on the internet.

Use this tool only on authorized systems

The utility intentionally checks one port per request and blocks private/reserved targets. It is intended for administrators verifying systems they own or have permission to test, not for broad scanning.