What it does
A Relayant box at the site connects out over an encrypted WireGuard tunnel. Nothing is opened or forwarded on the site's router.
Each device you choose gets one address and port. Any monitoring software that connects by address and port uses it, and it stays the same when the device moves on the site's network.
The box checks every device every minute and reports when one stops answering. Alerts go to the portal, email, Slack, Microsoft Teams and webhooks, and as alarm signals into your monitoring software.