// TOOLS · PORT SCAN
Port Lookup
A port number from your router's UPnP table, a scanner result or a firewall log. What is it, what does it mean that it is open, and does it matter.
PORT NUMBER
PORT 0
System port (0–1023): reserved by IANA for well-known services; on Unix-like systems only root can listen here. This port is not one we have written up; the port reference covers the ones that show up on home and small-office networks.
ON YOUR PHONE · PORT SCAN
Knowing what a port is only helps once you know which of your devices have it open. The app scans any host on your Wi-Fi, identifies the service on each port, and links straight to these pages. Get RECON for iPhone — one-time purchase, no account, nothing leaves the device.