Cisco 4500 - erase the startup config + VLAN.dat help

Associate
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I appreciate this is not in the networking section, but this is an 'enterprise' level piece of kit, and it's a work related Q.

Yesterday I was migrating a 4507 from one comms room to a different company's main comms room. I have knowledge up to CCNA on cisco stuff, so this was a bit out of my comfort zone, but I enjoyed the challenge.

Anyway, when I did a erase start and reload, firstly the console port I was on went into standby recover mode, with two options 'logout' or 'exit' - both of which were useless.

I had to then switch to the other console port - there were two ports on the front, and the other came live. The downside, my startup config wasnt erased, so I was back to my original problem.

When I tried to delete VLAN.dat from priv mode, I got the error 'you do not have permission to complete this action' or something very similar.

Now, the downside was, there was no internet connectivity in this building whatsoever, so after much head scratching, I decided to do a default interface on everything and 'no' everything else in the config. This worked fine, as did deleting the VLANs manually one by one.

When I looked today on cisco's website on how I should have achieved this, the help is not exactly clear:

http://www.cisco.com/en/US/docs/swi...g/command/reference/ch2a_ins.html#wpxref74065

So, how should I have erased the VLAN.dat file and the startup config without doing it the long winded way, and without erasing the IOS by accident!

This is more for my personal knowledge than to fix the problem... so any help appreciated :)

Thanks
 
Associate
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from Priv exec (youroutername#)

Write erase
(this deletes the config)

delete flash:vlan.dat
(removes vlan config and VTP config)

reload

This should do the trick - above all, until you've erased the vlan.dat don't connect it to a production network if it's in the same VTP domain.
If you do a 'show vtp stat' it'll show you the VTP domain and the config revision number, everytime you add / delete / change vlan information it'll increment the count - if this count is higher than the current revision on the network you connect it to (highly likely if you've been tinkering) then it'll wipe your current VTP information and replace it with it's own - has the potential to wipe all your vlan's!
(you'll see this in a cisco network as all your switchports will go orange...
 
Man of Honour
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London Town!
If you have redundant supervisors (Sounds like you do) then the official Cisco line is to remove the backup (slide it out), erase the primary and reboot. Then remove the primary, replace the secondary and erase that then reboot. Then power down, replace them both and you should be good to go. Slightly mad compared to most equipment but that's their line last time I heard...
 
Associate
OP
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Location
Preston, Lancs
If you have redundant supervisors (Sounds like you do) then the official Cisco line is to remove the backup (slide it out), erase the primary and reboot. Then remove the primary, replace the secondary and erase that then reboot. Then power down, replace them both and you should be good to go. Slightly mad compared to most equipment but that's their line last time I heard...

yup - this sounds like the problem. This was actually suggested and dismissed as crazy talk whilst I was on site :D

The supervisors must be designed to restore the config if you 'accidentally' delete it or something.

With regards to deleting vlan.dat - even in the priv mode I still go permission denied. I think there must be some form of unix-esque permissions on the flash card that had set it to read only.

I may be wrong. Anyway, thanks all for your help!
 
Associate
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Birmingham
I came across the same issue today on a Cisco 4500 with redundant supervisors and the 'pull them out one at a time' method worked a charm. :D

The only change was having to do erase cat4000_flash: rather than delete flash:vlan.dat to delete the VLAN config.
 
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