What it does
Port Checker provides a browser form for testing an IP address and port, with common-service presets and port-forwarding guidance.
Confirm the target IP and the port actually used by the service, choosing a preset only when it matches that configuration. Port Checker defaults to the address seen by the website but lets you enter another target. Its explanation warns that a VPN or proxy can make that detected address unsuitable for the device you intend to check. The result is an external observation of the selected port, useful for investigating a forwarding rule. A failure can involve the application, router, firewall or upstream provider; it does not identify one cause or establish reachability from every client.
Strengths
- Custom ports and common-service presets
Sources
- Port Checker - Check Open Ports Online (Oct 26, 2026)