Documentation

Ports PortPeek shows

What PortPeek lists: listening TCP and UDP sockets on IPv4 and IPv6, wildcard and localhost addresses, and why some sockets are missing.

Updated

PortPeek lists sockets that are listening and visible to your user account.

Kind Shown Notes
TCP listeners Yes State LISTEN only; established connections are hidden
UDP sockets Yes, where bound to a port Unbound or connected UDP sockets are skipped
IPv4 / IPv6 Yes 127.0.0.1, ::1, wildcard * and ::
Same port on IPv4 and IPv6 wildcard Merged One row instead of two

Addresses

  • 127.0.0.1:3000 / [::1]:3000 — reachable only from your Mac.
  • *:3000 — listening on all interfaces, reachable from your network.

What is not shown

Sockets owned by other users or system daemons running as root usually don’t appear, because PortPeek never asks for administrator rights. sudo lsof -nP -iTCP -sTCP:LISTEN in Terminal shows everything.

Discovery uses the system lsof tool behind a replaceable interface; a native backend may follow. See permissions.