Great site; however, there is no need to disable the DNS client. Just make sure you do not misspell anything... Just Kidding! If you have misspelled a command on the CLI the system attempts to make a telnet connection by first attempting a DNS lookup obviously. Having the DNS client is very useful and it is not necessary to disable it, it is just as easy to

CTRL+SHIFT+F6 then 6 and x

(Hold down the Control key (CTRL), SHIFT key, F6 key and 6 key at the same time, release then hit the x key)

hou01.agg01#exti
Translating "exti"...domain server (255.255.255.255) % Name lookup aborted

hou01.agg01#

There is no timing involved, and works with normal typing timing sequences.

This terminates a telnet session, and also actively aborts the DNS lookup