In this setup, we will see how to set up a check with Telnet and Zabbix. I personally don't see any reason for using Telnet anymore these days as there are plenty of other secure alternatives (Example, SSH). But just for the sys admin who likes to live on the edge or for the sys admin that has no other choice because of a company policy, this is it. (Remember that Telnet is not encrypted, so everybody can read your data!)
To make this setup work, all we need is a properly setup Zabbix server and a host with or without Zabbix agent as the check is initiated by the Zabbix server.