Which protocol is enabled if nothing is mentioned

[zeljkosan]

Hello guys, many thanks for help from you.

Quick question, if we have this in config:

line vty 0
exec-timeout 5 0
password somenthin
logging synchronous
login
length 0
line vty 1 4
exec-timeout 5 0
password somenthin
logging synchronous
login
line vty 5 15
exec-timeout 5 0
password somenthin
logging synchronous
login

Will both ssh and telnet work ? If nothing is mentioned, which protocol is allowed?

Br

[Kasun Bandara · Accepted solution]

@zeljkosan hi, be default devices using below command. so all protocols which supported by device will be enabled.

'transport input all'

[Jens Albrecht · Accepted solution]

Hello @zeljkosan,

you can check the default settings that are normally not displayed using the command "show run all" and apply the usual filters as needed. As an example the command "show run all | sec line vty" will display all settings on your VTY lines including the defaults.

On older software versions the default used to be 'transport input all' but newer versions now have a default of 'transport input telnet ssh' because Cisco removed the old legacy protocols like rlogin, mop or decnet due to security concerns.

Nevertheless, you can use telnet and ssh by default but turning off telnet is strongly recommended, of course.

HTH!

[zeljkosan]

Hello Jens and Kasun, thanks for help. Br