We've looked at quite a lot of fairly custom and customizable ways to get data into Zabbix. Although external checks should allow us to grab data by any means whatsoever, in some cases, we might need to collect data from some system that's reachable over SSH or even Telnet, but there's no way to install an agent on it. In that case, a more efficient way to retrieve the values would be to use the built-in SSH or Telnet support.