How to break Router's Password

Hi guys this topic is just for the understanding that in a critical condition when we wont be able to log in into our router we can use this method to get into it.

Router has basically 2 register mode
i) 0x2102 (Default mode)
ii) 0x2142 (troubleshoot mode)

Troubleshoot mode is basically the alternative method to dig into the router and this need a physical access with physical access we cant break the password of router.

Steps:

1. Restart the router(during restart process it goes to default mode and we have to stop it)
2. So in second step we use ctrl+pause/break button to avoid the default register mode.
3. Use command "confreg 0x2142" (this command is used to configure the register mode).
4. It will show the "rommon 2>" mode, here just use reset command.
5. Now the router will restart and open in 0x2142 mode.

It now asks for initial configuration just type NO.

Again use the commands like:

router>enable
router>show version
router>config t
here we are going to change the register mode
router(config)>config-register 0x2102
router(config)>line console 0
router(config)>no pass(it will not ask for the password)
router(config)>exit
router>exit
router>wr(for building configuration)

Now the router have no password.

IP Phone Boot up process

1. IP phone obtains power from the switch

2. Phone loads stored image

3. Switch provides VLAN information to IP phone using CDP.

4. Phone sends DHCP(provides IP address,default gateway and DNS) request;receives IP information and TFTP(option 150) server address.

5. IP Phone gets configuration from TFTP server

6. IP Phone registers with Cisco CallManager server which includes primary,secondary and tertiary servers.

**NOTE: A simple flowchart for the better understanding.