PUBLIC NETWORK UTILITY

TCP port checker

See whether one TCP port on a public server is reachable from Sentinel's network.

Common ports
What this checks

A single TCP handshake from the Sentinel server. It sends no application commands and reads no service banner.

What the result means

Open means a connection was accepted. A timeout cannot distinguish a closed port from one blocked by a firewall.

Built for safe use

One target and port per request, 20 checks per 15 minutes, with private, local, and reserved networks blocked.