Password Break of Cisco Router
Create a consol connection with the default setting
When its booting the IOS then hit “Ctrl+Break”
Then it will go to the ROMON Mode. it looks like
Romon>help
You need to change the register value. to see the register value
Romon>show version
originally the configuration register is 0x2102. To change the register value to 0x2142
Romon> confreg 0x2142
Then Restart the router
rommon> reset
The router now will restart and ask you if you want to use the setup mode and of course you will say no.
Now, in order not to loose the configuration that you already have in the router,
Router>enable
Router#copy start run
Router#configure terminal
Router(config)#enable secret abcd123
And you can also put new console and telnet passwords if you like. Click Here
To get things going back to normal, change the value of the configuration register to its original form (0x2102)
using the following global configuration command:
Router(config)#config-register 0x2102
Save the configuration including the new passwords that you know:
Router#copy run start
Then Restart the router
Router#reload