If you have forgotten the router’s enable secret password or someone has just given you a second-hand router, and you don’t know it, you need to decrypt it to configure it.
The first thing we need to do is to make sure that the IOS (operating system) is not loaded when the router is turned on, so press the
CTRL + BREAK keys for 60 seconds during boot. With this process, our device is opened with the operating system where mini IOS operations can be performed.
ROMMON mode. (ROMMON mode is like a small operating system.)
Now we change the configuration register with the command
o/r 0x2142. Our router will no longer load the configuration from NVRAM at boot.
Turn off the router (using the reload command). Now that our old employee configuration cannot be loaded, IOS asks us step-by-step to create a new configuration.
After answering this question “NO”, the router appears as the default command line.
startup-configurationto the router. The reason we do this is to ensure that the forgotten password is not reloaded.
router> enable when I type and press enter, we are now able to switch to enable mode.
router # sh startup-config; command, you can browse encrypted passwords.
rommon 3 > reset
Now let’s copy the initial configuration to the current running configuration.
Router#copy startup-config running-config
If the password was previously written with the enable password command, we have a chance to see the password, but if it is encrypted with enable secret, we cannot see it. So we need to enter
conf t mode and change the password.
Router> enablecommand to configure the device with the password we set.