Transport Preferred None
Have you ever mistyped a command and the router thinks you want to telnet another device? The most common solution is to turn off name lookups.
no ip domain-lookup
This will tell the router to not use DNS for looking up names and will
speed up the failing of the command. However if you need to have DNS
enabled we can’t use this solution.
line vty 0 4
transport preferred none
By default telnet is the preferred protocol and when mistyping the router
will try to telnet the “name” you typed. If we set it to none the router
won’t try to telnet when mistyping and you can have DNS enabled which is
the best of two worlds. If you want to telnet to another device you have
to type telnet 220.127.116.11 instead of just 18.104.22.168 but that is a small price