Contents
November 2014 9 How to clear, CMOS, DL380, Gen9, HP Server, NVRAM, reset, switch, switch 6 In case of POST errors and boot issues due to incorrect BIOS values initialization it might be necessary to clear/reset the CMOS and NVRAM of your HP Server Gen9. NVRAM reset and cold reset does not work 04:41 PM You have not performed the NVRAM reset which will reset all settings back to factory default, change the ip address and wipe other paramaters.
Introduction
In certain situations, it is desirable to restore the Catalyst switch configuration to the original default factory settings. This is useful when you want to remove an undesirable configuration that is present in the switch. If you have configured a switch and the configuration has become very complex or if you want to move a switch from one network to other, you can reset the switch to factory defaults and configure it as a new switch. This document provides information and sample command logs to reset your switches.
To reset the Catalyst switches to factory defaults, you need access to the switch console through either a physical console or a Telnet connection. You also need the console/enable passwords. If you forget the console and enable password of your switch, you cannot reset the switch configuration to factory default to reset the password. In this case, you need to follow the password recovery procedures for your switch. Refer to this document for steps to recover the passwords on your Catalyst switches:
Note: If you reset the switch to factory defaults while you access the switch by Telnet connection, you lose connectivity to the switch.
Prerequisites
Requirements
There are no specific requirements for this document.
Components Used
The information in this document was tested with these software and hardware versions:
Note: Although the document was created with these Catalyst switches, the principles apply to the products mentioned in the document.
- Catalyst 5505 switch with Catalyst OS (CatOS) version 6.4(8)
- Catalyst 2950 switch with Cisco IOS® Software Release 12.1(19)EA1
- Catalyst 6500/6000 switch with Cisco IOS Software Release 12.1(20)E
The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.
Conventions
For more information on document conventions, refer to the Cisco Technical Tips Conventions.
Before You Begin
Before you reset the switch to factory defaults, perform one of these tasks:
- Back up your configuration on a TFTP server.
- Copy your configuration to a text file.
- Copy the configuration locally on the bootflash or slot0: device.
Once you clear the user configuration, there is no way to recover the configuration unless you restore the backed-up configuration. To upload a configuration file on a TFTP server, refer to this document:
Note: You can restore the complete configuration if you copy the text file configuration and paste it to the command line.
Reset Catalyst Switches Running CatOS
This procedure applies to Catalyst 4500/4000, 5500/5000, and 6500/6000 series switches running CatOS. These switches store the configuration in NVRAM automatically, wherever users enter the commands in enable mode. On Cisco IOS Software, you must save the configuration with the write memory command or the copy running-config startup-config command. You can reset the system or module configuration on these switches running CatOS to factory defaults with the clear config command. The command syntax is:
The clear config all command clears the system configuration, as well as the module configuration. This command does not, however, clear the boot variables, such as config-register and boot system settings. You can alter the boot variable settings with the set boot command. If your switch has any router cards, the clear config all command does not clear the Cisco IOS Software configuration on the router cards. (Examples of these router cards include WS-X4232-L3 modules on the 4000 switches, Route Switch Modules [RSMs]/Route Switch Feature Cards [RSFCs] on the 5500/5000 switches, or the Multilayer Switch Modules [MSMs]/Multilayer Switch Feature Cards [MSFCs] on the 6500/6000 switches.) To clear the configuration on router cards, you can access the router card with the session command. Then, reset the switch to factory defaults with use of the procedure in the Reset Catalyst Switches Running Cisco IOS Software section of this document. This example shows how to reset the configuration on the switch to factory defaults:
After the configuration erase in CatOS, you do not need to reload the switch. The configuration takes effect immediately, and the switch returns to the factory default configuration. If you want to clear the configuration of a specific module on the switch, issue the clear config mod command, as shown here:
Reset Catalyst Switches Running Cisco IOS Software
The procedure in this section applies to the router cards, the modular or fixed configuration switches, and GL-3 Catalyst series switches running Cisco IOS Software:
- Router cards
- WS-X4232-L3 (Catalyst 4006/4000)
- RSM/RSFC (Catalyst 5500/5000)
- MSFC/MSM (Catalyst 6500/6000)
- Catalyst modular switches
- Catalyst 6500/6000
- Catalyst 4500/4000
- Catalyst fixed configuration switches
- Catalyst 2940
- Catalyst 2950/2955
- Catalyst 2970
- Catalyst 3550
- Catalyst 3560
- Catalyst 3750
- Catalyst 2900XL/3500XL
- GL-3 Catalyst switches
- Catalyst 2948G-L3
- Catalyst 4908G-L3
Switches running Cisco IOS Software have a running configuration file and a startup configuration file. The RAM stores the running configuration, and the NVRAM stores the startup configuration. When you make a configuration change to a switch running Cisco IOS Software, the change becomes part of the running configuration. You must save the configuration changes to the startup configuration; otherwise, the configuration is lost during the next reload or power outage. This is because you lose the running configuration stored in RAM when you reload the switch or turn off the power. To save the configuration into NVRAM, issue the write memory command or the copy running-config startup-config command. If you do not save your changes to NVRAM, the changes clear from RAM and are no longer part of the startup configuration when the switch reloads.
On the Catalyst modular or fixed configuration switches running Cisco IOS Software, a separate file stores the VLAN information. The file is called vlan.dat file and is stored in NVRAM for modular switches or in Flash for fixed configuration switches. To reset these switches to factory defaults, you need to delete the startup configuration and the vlan.dat file. To restore the Catalyst 2948G-L3/4908G-L3 switches and router cards to the factory defaults, you only need to delete the startup configuration file. These switches do not contain VLAN information because they do not participate in VLAN Trunk Protocol (VTP).
Reset Switch Configuration
To reset the switch to factory default, issue the erase startup-config or write erase command. This command does not clear the boot variables, such as config-register and boot system settings. You can alter the boot system parameters with the boot command. In Catalyst 4500/4000 and 6500/6000 series switches running Cisco IOS Software, you can change the configuration register value with the config-register command.
This example shows how to reset a switch running Cisco IOS Software to factory defaults with the write erase command:
At this stage, the switch configuration has reset to the factory defaults, with the exclusion of the VLAN information.
Reset VLAN Information
To reset the VLAN information to the factory defaults, delete the vlan.dat file from the Flash or NVRAM and reload the switch. On the 6500/6000 series switches running Cisco IOS Software, the vlan.dat file is stored in const_nvram. On the 4500/4000 series switches running Cisco IOS Software, the vlan.dat file is stored in cat4000_flash:. On the 2940, 2950/2955, 2970, 3550, 3550, 3560, 3570, and 2900XL/3500XL fixed configuration switches, the vlan.dat file is stored in flash:.
To erase the vlan.dat file on the 6500/6000 switches, issue the erase const_nvram: command. On the 4500/4000 switches, issue the erase cat4000_flash: command. On the fixed configuration switches, issue the delete flash:vlan.dat command.
The example steps show how to delete the VLAN information on Catalyst fixed configuration switches. You can use the same steps, with their respective commands, for the 6500/6000 and 4500/4000 running Cisco IOS Software:
- To verify the VLAN information, issue the show vlan command, and to verify the vlan.dat file, issue the dir command.
- Delete the VLAN information from Flash or NVRAM, and reload the switch.Note: On the 6500/6000 and 4500/4000 running early versions of Cisco IOS Software, the delete command may not work. Instead, you must issue the command erase const_nvram: or the command erase cat4000_flash:. Do not specify the vlan.dat file in the command syntax. However, on later versions of Cisco IOS Software, the delete const_nvram:vlan.dat command works for the 6500/6000, and the delete cat4000_flash:vlan.dat command works on the 4500/4000.
- After reload, check the VLAN information with the show vlan command.The user-configured VLANs no longer appear in the command output. Only factory-default VLAN information is on the switch.
Reset Catalyst Switches in Redundant Mode
For the 6500/6000 and 5500/5000 switches running CatOS in redundant mode, the standby Supervisor Engine synchronizes with changes made to the active Supervisor Engine. So, if you reset the configuration on the active Supervisor Engine to factory defaults with the clear config command, the standby Supervisor Engine also resets to factory defaults. Whether you set the configuration mode to binary or text mode with the set config mode command, the switch resets to factory defaults when you clear the configuration on the active Supervisor Engine.
To reset 6500/6000 switches running Cisco IOS Software in redundant mode to factory defaults, you need to complete these steps:
- Erase the startup configuration with the erase startup-config command on the active Supervisor Engine.Note: This also erases the startup configuration on the standby Supervisor Engine.
- Delete the vlan.dat file as shown in the Reset VLAN Information section of this document.
- Reload the active Supervisor Engine with the reload command
![Clear Nvram Ea2700 Clear Nvram Ea2700](https://setuprouter.com/router/cisco/linksys-ea2700/reset-71774.jpg)
Note: If the Supervisor Engine enters the ROMmon mode after it reloads, check the boot variable to see if it is set to boot from the proper image. You may also refer to the document Recovering a Catalyst 6500/6000 Running Cisco IOS System Software from a Corrupted or Missing Boot Loader Image or ROMmon Mode for further troubleshooting information.
Related Information
If you’re troubleshooting your Mac, you’ve probably seen this advice before: reset your NVRAM. Some forum denizens talk about this as a cure-all solution to Mac instabilities, but what is NVRAM? And what problems can it actually solve?
What Is NVRAM?
Let’s start by explaining what, exactly, NVRAM does. If you mute your Mac’s volume, then restart it, you won’t hear the iconic startup sound. How does your Mac pull that off? Because volume settings are stored in the NVRAM, which the Mac’s firmware has access to even before macOS begins booting. According to Apple’s official instructions, the NVRAM also stores things like screen resolution, time zone information, and, crucially, which hard drive to boot from.
![Clear Clear](/uploads/1/2/5/5/125530013/920428434.jpg)
This is all useful information for your system to have before it boots, but in some cases corrupt NVRAM can cause Mac glitches or even prevent macOS from starting. If you’re having trouble starting up your Mac, briefly seeing a question mark during boot, or finding that your Mac constantly boots from the wrong hard drive, clearing the NVRAM can help. It won’t fix everything, but it doesn’t generally hurt to try—though you may need to reset your time zone, resolution, or other settings like that if you’re using custom ones.
How to Reset Your NVRAM
If you want to reset your NVRAM, there are two main methods. The first (and most reliable) method starts with shutting down your computer. Next, hit the power button. As soon as you hear the startup sound, press and hold the Command, Option, P, and R keys together.
Hold the keys down. Eventually your Mac will restart, and you’ll hear the startup sound again. Feel free to let go of the keys when that happens. The NVRAM should be reset and your computer should start up normally.
If you own a late 2016 MacBook Pro (and presumably other Macs made since then) things work a little differently. Apple killed their classic startup sound, so you won’t hear it. Instead, just hit the keyboard shortcut right after turning on the Mac, then hold those keys for 20 seconds. Your NVRAM should be reset.
How to See What’s In Your NVRAM
Curious about what’s actually in your NVRAM? Open up the Terminal in macOS, which you’ll find in Applications > Utilities. Type
nvram -xp
, then press Enter. You’ll see the complete contents of your NVRAM.Don’t expect this to make for great reading. You’ll recognize a few things, like volume levels (pictured above), but you’ll also see a bunch of cryptic keys. What’s here will vary a lot depending on what kind of Mac you have, and other details about your device.
While we’ve got the Terminal open, it’s also possible to clear the NVRAM from here, with the command
nvram -c
. You’ll need to restart your Mac for the reset to complete, which is why the keyboard shortcut method above is generally considered a better bet.Clearing your NVRAM won’t solve all of your Mac’s problems, but it can solve some, particularly if you’re having trouble getting your Mac to boot. It’s also possibly a good idea if you’re having issues with your volume or screen resolution settings.
Photo credits: Christoph Bauer, EricRobson214
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