Cisco
Recover a lost enable password on Catalyst 2960/3560/3750 switches using the classic IOS config-register 0x2142 procedure over the console port.
This guide provides step-by-step instructions for resetting lost or forgotten administrative passwords on enterprise networking hardware. Follow the procedure below carefully to regain access while preserving your device configuration.
Before proceeding with password recovery, ensure you have a console cable, terminal emulation software configured to 9600 baud, and physical access to the device.
Connect your terminal cable to the console port of the device and open your serial terminal session.
Power cycle the hardware and issue a Break key sequence during initial system startup to enter ROMMON mode.
Bypass startup configuration loading, boot into system software, set your new credentials, and save changes back to non-volatile memory.
Catalyst 2960/3560/3750 run classic Cisco IOS. The recovery method is the standard IOS password-recovery procedure: boot with the configuration register set to 0x2142 so the switch ignores its startup configuration, then merge it back.
switch: prompt.switch: flash_initswitch: load_helperswitch: confreg 0x2142switch: bootSwitch> enableSwitch# copy startup-config running-configSwitch(config)# enable secret <new-password>Switch(config)# config-register 0x2102Switch(config)# endSwitch# write memorySwitch# reloadIf copy startup-config running-config reports errors, the saved configuration may contain commands the temporary image does not support — the passwords will still be cleared, and you can restore the rest from a backup.