SSH provides remote access and control through key pair authentication.

Environment: the company's e-commerce site is configured and maintained by a dedicated webmaster and needs to be managed remotely from Internet at any time. For ease of use and flexibility, OpenSSH service is enabled on the Web server, and strict control of SSH login is required for security reasons. The environment is shown below:

Experimental requirements: allow administrator wzadm to pass through the external network testing machine, using key pair verification to improve security

Allow user jacky to log in to the server remotely through the client, but only from 192.168.1.20

Prohibit other users from logging in to the server remotely through SSH

Note: this experiment requires the use of GNS3 simulator, to use a switch and a router to connect to the server, if you can not use GNS3, then you have to use a real device to do, about GNS3 can check the relevant usage on the Internet, just connect the connection mode of the analog device to the network card of the virtual machine

The steps of the experiment: