One of the most widely used applications of Secure Shell-based products is to replace the unsecured login protocols, Rlogin, Telnet, and FTP, with secure alternatives. The Tectia client/server solution is based on SSH Secure Shell, used worldwide for secure system administration.

Figure 5.1 shows a typical Tectia environment for secure system administration. In this example, the managed servers reside in the perimeter network (DMZ), and the system administrator connects to them over the Internet using Tectia Client. In this scenario, Tectia Client software is installed in the system administrator's workstation and the Tectia Server software in the managed server. Tectia Server for IBM z/OS could be running at either end of the connection.

Figure 5.1. Secure system administration with Tectia client/server solution