CISCO NETWORKING ACADEMY Chabot College ELEC telnet

CISCO NETWORKING ACADEMY telnet Uses services of Layers 7 - 1

CISCO NETWORKING ACADEMY telnet Functions: –Tests layers –Remote access over the network to virtual terminal console of router. Useful for remote administration.

CISCO NETWORKING ACADEMY telnet Listener: –by default, hosts “listen” on port 23 –telnet listener called “daemon” on unix, “service” on NT –Cisco routers listen for telnet on port 23 –telnet login should be controlled with password.

CISCO NETWORKING ACADEMY telnet When you telnet to a remote router, your screen shows the remote router’s prompt: hayward# telnet fremont trying …open User access verification Password: fremont> hayward fremont

CISCO NETWORKING ACADEMY telnet When you exit your telnet session on a remote router, you return to the previous router’s prompt: hayward# telnet fremont trying …open User access verification Password: fremont> exit hayward# hayward fremont

CISCO NETWORKING ACADEMY telnet - out & back As you telnet from ‘hayward’ to other routers, you can return to your “home” router each time: hayward oakland sanfranciso hayward oakland sanfranciso hayward oakland sanfranciso telnet to oakland telnet to sanfranciso home router exit oakland

CISCO NETWORKING ACADEMY telnet - daisy chain As you telnet from router to router, you can “daisy chain” your sessions: hayward oakland sanfranciso hayward oakland sanfranciso telnet to oakland telnet to sanfranciso home router

CISCO NETWORKING ACADEMY telnet - daisy chain As you you exit, you will return one hop at a time along the chain: hayward oakland sanfranciso hayward oakland sanfranciso telnet to oakland telnet to sanfranciso home router hayward oakland sanfranciso exit oakland hayward oakland sanfranciso exit sanfrancisco

CISCO NETWORKING ACADEMY IOS telnet Commands To telnet to another router, use any of these: hayward# telnet hayward# connect hayward# hayward

CISCO NETWORKING ACADEMY IOS telnet Commands You may also use host names, but only if –DNS services are running and enabled, or –your router has an IP host table in its config hayward# telnet fremont hayward# connect fremont hayward# fremont hayward fremont ( )

CISCO NETWORKING ACADEMY IOS telnet Commands To exit your telnet session and return to the previous router’s prompt, use any of these: fremont> exit hayward# hayward fremont fremont> logout hayward#

CISCO NETWORKING ACADEMY telnet - exit Be sure to exit your telnet session when done! Don’t just close your hyperterm session and leave yourself connected to the remote router. If you don’t exit, the VTY port you were using will remain busy and unusuable by other students. Remember, there are only 5 VTY ports! fremont> exit hayward#

CISCO NETWORKING ACADEMY telnet practice - Router e_SIM Try it now with Router e-SIM: –Start Router e-SIM –Give all your routers a configuration: click SHOW DONE in the row of SET buttons at the bottom, click A, B, C, D, E click HIDE DONE –Login - Password - cisco Limitations: Router e-SIM understands only these commands: –telnet xxx.xxx.xxx.xxx (IP Address) –exit

CISCO NETWORKING ACADEMY telnet practice - Router e_SIM Try these, in order: Lab_A> telnet Lab_B> exit Lab_A> telnet Lab_C> exit Lab_A> telnet Lab_E> exit Lab_A> telnet Lab_B> telnet Lab_C> telnet Lab_D> telnet Lab_E> exit Lab_D> exit Lab_C> exit Lab_B> exit Lab_A> Out & back Daisy chain