How to Erase the Config and VLAN Database on a Cisco Switch or Router

How to Erase the Config and VLAN Database on a Cisco Switch or Router

Erasing the config on a Cisco Switch or router becomes necessary at times for either disposal or re-purposing into a new location or lab environment.

NOTE: I highly recommend that before you delete any configuration from a switch or router you take a backup for the config and the vlan.dat . The one time you will need this is the one time you dont have it, and its good practice for archival purposes. 

Firstly, you need to erase the startup configuration. to do this two commands are used - either write erase or the newer erase startup-config. 

On a Catalyst Switch, you may need to to erase the VLAN database. To do this, type you type the command delete flash:vlan.dat 

From here you need to reload the router / switch. When running the reboot you will be prompted that system configuration has been modified, Save? [yes/no] Here, you should choose no . or you will write the running config back to the startup config and have to repeat the process!

This article can also be found at our sister site DizzyIT.com at: http://dizzyit.com/2013/03/29/erase-config-vlan-database-cisco-switch-router/