About this tool
Common TCP and UDP ports, what uses them, and whether they should face the internet. This tool works entirely in your browser. Nothing you type is sent anywhere.
Free to use, no sign-up. We don’t log or store what you look up.
Review your firewall rules too
Paste a config from 12 firewall platforms — plus switches, Wi-Fi, NAC, Azure NSG, NetScaler, F5 and more — and get a graded review with fix commands, mapped to 16 standards. The config never leaves your browser.
Start free See a sample report