DelarosaSchwartz758

CCNA and CCNP candidates who have their own Cisco home labs often e-mail me about an odd scenario that happens when they erase a switch's configuration. Their startup configuration is gone, as they anticipate, but the VLAN and VTP information is nevertheless there!

Sounds odd, does not it? Let's appear at an example. On SW1, we run display vlan brief and see in this abbreviated output that there are 3 extra vlans in use:

SW1#display vlan br

ten  VLAN0010                         active

20  VLAN0020                         active

30  VLAN0030                         active

We want to entirely erase the router's startup configuration, so we use the publish erase command, confirm it, and reload without saving the operating config:

SW1#write erase

Erasing the nvram filesystem will eliminate all configuration files! Continue?

[confirm]

[OK]

Erase of nvram: full

00:06:00: %SYS-7-NV_BLOCK_INIT: Initalized the geometry of nvram

SW1#reload

Technique configuration has been modified. Conserve? [yes/no]: n

Proceed with reload? [confirm]

The router reloads, and right after exiting setup mode, we run display vlan brief once again. And even even though the startup configuration was erased, the vlans are nevertheless there!

Switch#display vlan br

ten  VLAN0010                         active

20  VLAN0020                         active

30  VLAN0030                         active

The reason is that this vlan and VTP information is in fact kept in the VLAN.DAT file in Flash memory, and the contents of Flash are kept on a reload. The file has to be deleted manually.

There's a little trick to deleting this file. The switch will prompt you twice to ask if you actually want to get rid of this file. Do not variety "y" or "yes" just accept the defaults by hitting the return essential. If you type "y", the router attempts to delete a file named "y", as shown right here:

Switch#delete vlan.dat

Delete filename [vlan.dat]? y

Delete flash:y? [confirm]

%Error deleting flash:y (No such file or directory)

Switch#delete vlan.dat

Delete filename [vlan.dat]?

Delete flash:vlan.dat? [confirm]

Switch#

The very best way to prepare for CCNA and CCNP exam good results is by working on real Cisco equipment, and by performing lab tasks over and more than. Repetition is the mother of skill, and by definitely erasing your VLAN and VTP info by deleting the vlan.dat file from Flash, you are going to be building your Cisco capabilities to the point exactly where your CCNA and CCNP exam accomplishment is a certainty. learn about yamaha motorcycles