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Chabot College. ELEC 99.08 telnet. telnet. Uses services of Layers 7 - 1. telnet. Functions: Tests layers 7 - 1 Remote access over the network to virtual terminal console of router. Useful for remote administration. telnet. Listener: by default, hosts “listen” on port 23
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Chabot College ELEC 99.08 telnet
telnet • Uses services of Layers 7 - 1
telnet • Functions: • Tests layers 7 - 1 • Remote access over the network to virtual terminal console of router. Useful for remote administration.
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.
telnet • When you telnet to a remote router, your screen shows the remote router’s prompt: hayward# telnet fremont trying 10.2.0.1…open User access verification Password: fremont> hayward fremont
telnet • When you exit your telnet session on a remote router, you return to the previous router’s prompt: hayward# telnet fremont trying 10.2.0.1…open User access verification Password: fremont> exit hayward# hayward fremont
hayward oakland sanfranciso sanfranciso oakland hayward oakland hayward sanfranciso telnet - out & back • As you telnet from ‘hayward’ to other routers, you can return to your “home” router each time: home router telnet to oakland exit oakland telnet to sanfranciso
hayward oakland sanfranciso oakland hayward sanfranciso telnet - daisy chain • As you telnet from router to router, you can “daisy chain” your sessions: home router telnet to oakland telnet to sanfranciso
hayward hayward oakland oakland sanfranciso sanfranciso sanfranciso oakland hayward oakland hayward sanfranciso telnet - daisy chain • As you you exit, you will return one hop at a time along the chain: home router telnet to oakland telnet to sanfranciso exit sanfrancisco exit oakland
IOS telnet Commands • To telnet to another router, use any of these: hayward# telnet 10.0.2.1 hayward# connect 10.0.2.1 hayward# 10.0.2.1 hayward 10.0.2.1
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 (10.0.2.1)
IOS telnet Commands • To exit your telnet session and return to the previous router’s prompt, use any of these: fremont> exit hayward# fremont> logout hayward# hayward fremont
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#
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
telnet practice - Router e_SIM • Try these, in order: Lab_A> telnet 201.100.11.2 Lab_B> exit Lab_A> telnet 199.6.13.2 Lab_C> exit Lab_A> telnet 210.93.105.2 Lab_E> exit Out & back Lab_A> telnet 201.100.11.2 Lab_B> telnet 199.6.13.2 Lab_C> telnet 204.204.7.2 Lab_D> telnet 210.93.105.2 Lab_E> exit Lab_D> exit Lab_C> exit Lab_B> exit Lab_A> Daisy chain