3750 Switch Password Recovery

While having a class of CCNP-SWITCH, i had to perform some labs using layer-3 switch, i used cisco-3750 for the lab, i found that two of the switches are password protected as we purchased that few days before so i had to recvoer the password. Connect the PC to the console port of the switch and if switch is power on, unplug the power and again plug power and press the mode button (it depends on series to series for how long you have to press mode button untill the light turn to green then release it, in 3750 you may required to press for around 15-seconds).

The switch should then give you this prompt

switch:

To initialize the flash file system, run the command

switch: flash_init

The switch will now print few messages about the flash memeory, now the next command will be the helper command.

switch: load_helper

Now we have to list the contents of our flash memory using folowing command.switch:

swith: dir flash:

This will display you the output somewhat like this as show below
The switch file system appears:

Directory of flash:
13 drwx 192 Mar 01 1993 22:30:48 c3750-ipservices-mz-122-25.SEB
11 -rwx 5825 Mar 01 1993 22:31:59 config.text
18 -rwx 720 Mar 01 1993 02:21:30 vlan.dat
16128000 bytes total (10003456 bytes free)

Now rename the configuration file to be used later on.

switch: rename flash:config.text flash:oldconfig.text

To further boot the switch run the boot command, this will start the boot you are used to.

switch: boot

When the switch is booted up, you will realize that the configuration is lost But you are enabled on the switch now and we can recover our old configuration as we kept that in flash with different name.

To recover the old configuration:

Switch# rename flash:oldconfig.text flash:config.text

And now to replace the running configuration with the backup

Switch# copy flash:config.text running-config
Destination filename [running-config]?

Press enter, and you will have your old switch configuration back and you are enabled but remember to change your password now.

I hope this will be informative for you.

Cheers :)

Configuration Lost While Password Recovering

I was asked to troubleshoot a problem in IMSciences network, actually they were unable to connect to Islamabad HEC office (Vedio Confencing) and they also need to send the vedio trafic and voice traffic using one interface on router (3800-series) so after some research i have done with the problem and sloved for it. Actually i done with some VLAN configuration, Define some static Routes, enable routing, use sub interfaces and i was successfull to ping the destination.

Then the person who called me for the problem solution told me about the mistake of MS student who is working there as a internee while recovering password. IMSciences lost their startup configurations and face trouble both by the institute and the student as they get disconnected from the network, now they were unable to do the configuration, any how they ship the router back to PTCL for configurations.

So here i am going to tell you about the step that you must take care of while recovering your router password.

1: Boot your router and interrupt the boot sequence by performing a break sequence using Ctrl+Break key combination.

2: Change the configuration register to turn on bit 6 (0x2142)

rommon> confreg 0x2142
You must reset or power cycle for new config to take effect

3: Reload the router, type reset
The router will reload and ask if you want to enter setup mode, so your answer will be NO

4: Enter Privileged mode

Router > enable
Router #

NOTE: Now this is the step where you to take care many people just change the password and copy the configuration to startup configuration and here they make a mistake as you over-write the whole (original) configurations. so the correct sequence is:

5: Copy the startup-configuration to running-configuration

Router # copy startup-config running-config

6: change the password

Router # config terminal
Router (config) # enable secret cisco


7: Reset the configuration register to the default value


Router (config) # config-register 0x2102

8: save your configurations

Router # copy running-config startup-config

9: Relaod your router

Cheers