Category Archives: Cisco

How to: Recover Cisco configuration and access when password is lost

When loosing your credentials on a Cisco router, you can recover it all if you have physical access to it. You have to connect with the console cable and do the following:

Turn off Device
Turn on Device
Press CTRL C or CTRL Break Until rommon 1> shows
Enter confreg

Select as below:
do you wish to change the configuration? y/n [n]: y
enable “diagnostic mode”? y/n [n]:
enable “use net in IP bcast address”? y/n [n]:
disable “load rom after netboot fails”? y/n [n]:
enable “use all zero broadcast”? y/n [n]:
enable “break/abort has effect”? y/n [n]:
enable “ignore system config info”? y/n [n]: y
change console baud rate? y/n [n]:
change the boot characteristics? y/n [n]:
Configuration Summary
(Virtual Configuration Register: 0x2142)
enabled are:
load rom after netboot fails
ignore system config info
console baud: 9600
boot: image specified by the boot system commands
or default to: cisco2-
do you wish to change the configuration? y/n [n]: n
You must reset or power cycle for new config to take effect

Enter reset
Wait for 2 minutes, turn off and on the device
Would you like to enter the initial configuration dialog? [yes/no]: no

Press enter to start
You should see Router>
Enter ena
Enter copy start run

Enter conf t
Enter user admin privilege 15 password 4dm1n
Enter enable secret 4dm1n (or whatever)
If need by change the VTY passwords
Enter copy run start

Enter do sh ver to see the register
Configuration register is 0x2142
Now enter config-register 0x2102
Enter do sh ver to confirm the register has been updated
Enter copy run start
Restart Router

Make sure no shut on all interface


Fix: Cisco router looses configuration after reboot

One time when I encountered this after a reboot of the device, being a Cisco router or Switch or Wireless Device, I get back to factory settings. After some research I found out that the device is bypassing the startup configuration. This is what you get after a reboot:

--- System Configuration Dialog ---
Would you like to enter the initial configuration dialog? [yes/no]:

To fix this answer no to the question and press enter and type the following.

show version

If you notice Configuration register is 0x2142 in the information displayed, then type the following

configure terminal
config-register 0x2102

And when asked if you want to save the configuration, type no

Some other Configuration Register codes and what they mean. The list below have been taken from the Cisco website.

0x0000-0x000F | Boot Field Parameters 0x0000 Stays at the system bootstrap prompt 0x0001 Boots system image on EPROM 0x0002-0x000F Specifies a default netboot filename.
0x0040 | Ignore NVRAM contents.
0x0080 | OEM bit enabled to exclude details in boot messages.
0x0100 | Break disabled
0x0400 | IP broadcast with all zeros
0x800-0x1000 | Console line speed
0x2000 | Boot default ROM software if network boot fails
0x4000 | IP broadcasts do not have net numbers
0x8000 | Enable diagnostic message and ignore NVRAM contents


How to: Setup the initial IP address for Cisco NSS322

When plugging in the Cisco Smart Storage for the first time, setting up the IP Address can be a bit tricky and the setup CD isn’t quite plain and simple. So to setup the IP address manually plug in a monitor and a keyboard to the device and once the login process comes up, use the default username and password i.e. admin/admin.

Once you log in, type the following to set the IP Address:

ifconfig eth0 netmask up
ifconfig eth0

You should see the IP address configured and all there is now to do is enter the address in your browser and access the web interface of the device.