Check that a port is listening.

Health › checks. Pick Port listening on this machine. The agent looks at its own listeners. There is no host to type.

This is local. A port on another machine is the share check.

Pick Port listening on this machine

Open the machine, then health › checks. The primitive is Port listening on this machine. Port is the only field. On Accounts server, 22 is SSH. If sshd stops, the check fails even though the machine is still online. Check that a share or port answers is how Reception PC would test that same port from across the LAN.

Checks editor with a listening-port check for port 22 — Accounts server. Port 22 must be listening. Not added yet.

Add to list, then push

Press add to list. The check sits in the document. Push to agent is the next click, and it asks you to confirm. Push replaces the whole document. This shot stops before that, so nothing has been sent. When nothing is listening on that port, the alert is a check failure.

Checks list with a listening-port check named SSH is listening, not yet pushed — SSH is listening is on the list. Push has not been pressed.

Push is a two-step button. The agent must be online to evaluate. You can still add the check while it is offline, and it applies at the next hello. Reaching another machine's port is Check that a share or port answers.