1.1 Secure Login and Telnet Disabling - Disable telnet server
From the perspective of security, the management plane should support at least the SSH/SSL login mode. Ordinary plain text Telnet/ftp login is vulnerable to attack, and such secure login modes as SSH and SFTP should be supported. The session validity period must be limited.
It is recommended to disable telnet server. Disable telnet server by running: ZXR10 (config)#line telnet server disable