Friday, 27 May 2011

Reset Cisco Router Password using Minicom

Suppose you have a cisco router with configuration and password set. Today, I am going to tell you how to reset the Cisco router using Minicom (linux application).

Install MiniCom in fedora:
To install minicom in fedora type
# yum install minicom

Configure Minicom:
The configuration has to be done as root or user with root privilege.
# minicom -s or #minicom -s -c on
The -c on will enable the colour mode on.

Use the 'Up/Down' arrow to select "Serial port setup" and press "Enter".
Now type A to change serial device. Here, you have to know which tty is assigned for serial port. To know that type,

$ dmesg | grep ttyS
[ 1.297446] serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
[ 1.297896] 00:06: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A

So, In this case tty for serail port is ttyS0.
Select "E", now change the "Bps/Par/Bits" to "Current: 9600 8N1"or something else by pressing "A" next or "B" previous or using default C = 9600, D = 38400 and E=115200. Press "Enter".
Select "F", to disable Hardware Flow Control and press "Enter" to save the settings and exit back to the configuration menu.



Use the "Up/Down" arrow to select the "Save setup as dfl".
Now, your configuration is saved.
From now type
$ minicom or minicom -c on
as a normal user to connect with the Router.

Note: for more info about available functions in minicom
$ minicom
Now, press Ctrl+A, then Z for help

Reset Password:
First, Power off the Cisco router then Power on again. When the moment after CISCO ISO will be Self decompressing the image, you have to send the router the break signal as it is booting. In minicom, press Ctrl+A then F to send break signal.
This should bring you to the "rommon" prompt:
rommon 1 >

Now, for the rest part I guess you already know and don't have to write here....
Thou, if you need I will write it for you.

8 comments:

  1. I tried this the other day and it worked perfectly. Thank you very much
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  2. The pictures aren't showing at all, I sure hope that this tutorial will help me on my router problem. The password always resets itself.

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  3. Cisco router is one of the most required routers to build your home networks; however, end-users are commonly challenged to setup the device in the home, office, or other locations. Great post.

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  4. Totally aggressive information you shared here i am really so inspired here could you more share here i will be back to you as soon as possible keep continue sharing.
    Thanks




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