Cisco switches have a called nvram: memory, similar to the PC's hard disk, data is not lost when the power is cut off, the switch configuration is stored in nvram, inside, a configuration file called startup - config, as long as the configuration is saved, nvram: will be the startup - config this file inside, when the switch startup, reads nvram: the startup - inside the config file, if there is a password, we will not be able to enter enable mode, need tips here, in the Cisco low types of switches, such as 3750 (including 3750), under the nvram: the startup - inside the config file will flash at the same time: memory regeneration as a config. The text file, note the two files belong to the same file, delete any one, and two at the same time lost; In high types of switches, such as more than 4500 series (including 45 series), only the nvram: that is not called flash: the memory, so there is no config. The text this file, and flash: memory corresponding to memory is called the bootflash:, in addition to the IOS file on the inside, there is no other,
So we have under the condition of the enable password on the switch, and to remove the password, only need to switch is not read nvram: the startup - config,
Steps
The first case (below 3750 series)
(1) usually in front of the switch panel (port side) in the face on the left, there is a known as the "mode" button, hold down the button with the hand, and then pull the switch power supply cord, after 5 seconds again back to the power cord, if it is 3550, then will see the switches all ports will be bright, wait until the switch port put out after the first, then release the button hand; If is 3560, the port the light not bright, but the left panel lights flashing, wait until the first light to green flash, not let go of the hand and press the button (other switches similar model), then will see the landing switch interface the following
Switch:
(2) we want to get rid of nvram: startup - in the config file, make the switch can not find this configuration file, and think that there is no password, but we have flash: the config. The text can,
Switch: flash_init initialization (flash file systems)
Switch: load_helper auxiliary image (load and initialize ROM the smallest IOS image)
Switch: dir flash: (display flash files within the files and directories)
Switch: rename flash: config. Text flash: config. Old (modify the configuration file name, to skip the password)
Switch: the boot (restart)
(3) at this moment we don't need the enable password can smoothly enter the switch mode, but the switch does not load any configuration, at this point we can change the configuration file name in the enable mode back to config. The text:
Swith# rename flash: config. Old flash: config. Text
Then the configuration import memory works
Switch# copy startup - config running - config
Then change before you forget the enable password, and previous configuration is not lost,
The Switch (config) # no enable secret
The second case (more than 4500 series)
(1) of power switches directly unplug, and repeatedly press CTRL C two key combination, until
Rommon 1 & gt;
Mode,
(2) input confreg:
Rommon 1 & gt; Confreg
(3) according to the following situation choose
The Configuration Summary
=> The load ROM after netboot fails
=> The console baud: 9600
=> Autoboot from: commands specified in the 'BOOT' environment variable
Do you wish to change the configuration? Y/n [n] : y (important)
Enable "the diagnostic mode"? Y/n [n] : n
Enable "use.net in IP bcast address?" Y/n [n] : n
Disable the load "ROM after netboot fails?" " Y/n [n] : n
Enable "use all zero broadcast"? Y/n [n] : n
Enable "break/abort has effect"? Y/n [n] : n
Enable "ignore system config info"? Y/n [n] : y (important)
Change the console baud rate? Y/n [n] : n
Change the boot characteristics? Y/n [n] : n
The Configuration Summary:
=> The load ROM after netboot fails
=> Ignore the system config info
=> The console baud: 9600
=> Autoboot from: commands specified in the 'BOOT' environment variable
Do you wish to save this configuration? Y/n [n] : y (important)
You must reset or power cycle for the new configuration to take effect
Rommon 2 & gt; Reset (last restart)
(4) don't need at this time the enable password can enter the switch mode, but the switch at this time is according to the default boot methods start from CF card system, if there is no CF card, then restart the switch again, will again into rommon 1 & gt; This pattern, so must now change the switch boot mode to bootflash: in the IOS launched,
If there is only one of bootflash: IOS, then the input:
The Switch (config) # boot system bootflash:
If the bootflash: there are two file name is a. respectively in and b.b in IOS, such as from a. in guide,
Input:
The Switch (config) # boot system bootflash: a. in
(5) the last save all changes to the information: Switch# write
This article reprinted: xiamen network little thoughts
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