Disable Telnet

Overview 

This article will walk you through disabling Telnet: "stopping operations manager from listening on tcp port 23" 

Command Line

Please login the CLI with root

1.  Enter the following command to disable telnet. 
   sed -i '/server/a \\tdisable = yes' /etc/xinetd.d/telnet
   This will add a disable command to xinetd that is listening for telnet by default.
2. Enter the below command to verify the change has been entered.  
   cat /etc/xinetd.d/telnet
   It should look like this. 
   
3. Enter the below command to restart xinetd. This needs to be done to make sure xinetd is no longer binding on port 23.
   systemctl restart xinetd