$ sudo apt-get update
$ sudo apt-get install dcap-tunnel-telnet 

dcap-tunnel-telnet is installed in your system.

Make ensure the dcap-tunnel-telnet package were installed using the commands given below,

$ sudo dpkg-query -l | grep dcap-tunnel-telnet *

You will get with dcap-tunnel-telnet package name, version, architecture and description in a table

dcap-tunnel-telnet package basic information: