Cisco notes 101

cdp timer   10  -> how often cdp packet transmited out all active interface.  (19sec)
cdp holdtime 5  -> amount time device wil hold packet received from neighbor address.  (5 sec)


no cdp run -> turn off cdp all interface
no cdp enable-> turn off cdp neihgboor on one interface
cdp enabl.



show cdp neighbor          -> show list devices directly connected neighbor
show cdp *                 -> show all directly connected information
show cdp * protocol        -> check directly connected device IP ADDRESS
show cdp entry * version   -> list all directly connected devices
show cdp traffic           -> check traffic!


show cdp interface         -> check interface status



from show running config we can get ip information!
from cdp neighbor we can mapping directly connected devices!


^ best tool for information gathering.
^ can create topology!




!! how to configure telnet !!

activate telnet on router:

- conf t
- line vty 0 807
- password telnet
- login
- ^Z




ctrl+shift6+x    ->  back to original router but keep session alive.
enter twice      ->  back to remote router ( after ctrl + shift +  6 )

#show session -> checking session ( who logged on to this device)




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no ip domain-lookup      -> disable ip domain lookup  ( if wrong input command cisco will search from dns ).
ip domain-lookup         -> enable ip domain lookup
ip name-server 192.168.10.1    -> setting domain server
ip domain-name toro.com       -> appends domain name to host name  (FQDN)
sh hosts                     -> check domain and check domain cached information from host table


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debug all -> turn on debug all ( turn debug all on ->> carefull with high traffic router / switch  as it can make the device hang up :) )
no debug all -> turn off all
debug ip rip ->  debug rip




^ proceed with caution!!   check router utilization first!   using command:

show process -> showing process. ( if cpu utilization 50% ++ carefull to turn debug all).