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DEMO: Resetting Devices

Resetting a Cisco switch to factory defaults requires erasing the startup configuration and deleting the vlan.dat file from flash memory. Both steps are necessary to ensure no previous settings persist after a reload.

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About this video

Returning a Cisco switch to a completely unconfigured state is a two-part process, and skipping either step will leave residual settings on the device. The first step is erasing the startup configuration using the erase startup-config command, which wipes saved interface assignments, passwords, hostname settings, and other parameters stored in NVRAM. Once confirmed, the switch will no longer load those settings on the next boot. However, VLAN information is stored separately in a file called vlan.dat, which resides in flash memory and is not removed by erasing the startup config. This file is created automatically when VLANs are configured and persists across reloads independently of NVRAM. To confirm its presence, the show flash command displays the contents of flash storage. Removing vlan.dat requires issuing the delete vlan.dat command and confirming the prompt. Only after both the startup configuration and the vlan.dat file have been removed will a reload produce a fully clean switch with no inherited settings. This two-step reset procedure is standard practice when repurposing or troubleshooting Cisco switches, and understanding it prevents configuration conflicts that can be difficult to trace when only one of the two steps is performed.

What you'll learn

What's covered

Factory Reset Switch

Aligned to

Cisco CCNA
2.1 Configure and verify VLANs (normal range) spanning multiple switches
Cisco CCST Networking
4.5 Explain basic switching concepts
5.5 Run basic show commands on a Cisco network device

Key terms

Switch
A network device that connects devices within a LAN and forwards traffic based on MAC addresses.
Virtual LAN
VLAN
A logical grouping of network devices that behave as if they are on the same network regardless of physical location.
Startup Configuration
A saved configuration file stored in NVRAM that is loaded into RAM during the boot process to configure the device's settings and parameters.
Flash Memory
A type of non-volatile solid-state memory that stores data on chips and retains information without power; it is the storage technology behind SSDs, USB drives, and SD cards.
vlan.dat
A file stored in a Cisco switch's flash memory that contains VLAN configuration data and must be deleted to fully reset the switch to factory defaults.

Topics

Cisco Switch Factory Reset Startup Configuration Vlan Network Device Management Networking

Transcript

Let's say I want to now completely start fresh. I want to wipe everything out and start with an all fresh switch, with none of the configurations.

One of the obvious things that I need to do is erase the startup config, so: erase startup config. I'm going to erase this, and this is going to wipe that file out. So I hit there, it says are you sure, and yes I do, and so now it is complete.

Now I would think at this point in time that if I did a reload, my switch would come up and there wouldn't be any configurations to it. However, I do actually have an extra file on here. Later on we're going to be getting into VLANs, and when we start covering VLANs there is going to be an extra file that's going to be created. So if I do a show flash on here, I can see that on this switch I actually do have this vlan.dat. If I were to restart this, that file would still exist.

So if I truly want to start with a fresh slate and not have anything on this switch programmed at all, I need to remove that. I do that by typing in delete vlan.dat. It's going to confirm, am I sure that I want to do that? Yes. And confirm. And then it is removed.

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