title: Use check_mk_agents on clients to check availability of a service or host
body: <p>I hope it's ok to ask rather a settings question instead of a coding-question here.</p>
  <p>We are using CheckMK now to monitor some of our services/ servers. We want to use a bunch of clients (in this case raspberry pis, about 150 of them in total) to check if a service is available to them.</p>
  <p>The Check-MK server monitors 3 of our servers and several raspberries with the standard deb-package installed on them. Now we see if a server is available and if an rpi is available.
  We would like to monitor, if the monitored servers are available from the rpi too. Not just from the Check-MK server.
  Reason: The Network is quite big and it is possible that the monitoring-server and the servers which are monitored can communicate, but some rpis are not able to connect to services on those servers.
  We want to track down the connection-issues. They seem to be firewall/ hardware related.
  So basically I try to use a agent/ client to ping something and report this to check_mk.
  Is this possible? I had no luck finding a rule or a setting for this which would be suitable.</p>
  <p>Maybe we need a custom API-CALL/ Skript for this?</p>
  <p>Thanks in advance
  Exa</p>