notifications when no data is received from remote host for a period of time

[Boghdan]

Is there any way i could be notified (using trigger or straight notification) if the zabbix-server doesn't get any data from certain active agents for lets say 5min. Just trying to figure out a way how to monitor availability of servers that are running on another network which doesn't use zabbix proxy. Agents send data directly to certain port on our ISA server, where the connection is redirrected to the zabbix-server.

[richlv]

agent.ping item with a nodata() trigger is a commonly used combination for that