Is the only way to tell if the agent is up is by the Devices tab? Is there a way to get an alert if the agent has not responded in a period of time? I looked at policies, but it assume that the agent can talk back to the server to report on an action.
I believe you should find this helpful: https://help.comodo.com/topic-289-1-719-8565-Managing-Policies.html
It explains Policy settings and one of the options include: "
| Ping Monitor
|| Pings a device using its hostname, fully qualified domain name or an IP Address and triggers an alert if no response is received.
That should generate an alert if the specified Agent is no longer reachable.