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New Member

Really long MAC address?

I am trying to setup AUTOINSTALL on a catalyst 2950. I have been successfull but I am slightly confused.

I am creating a DHCP reservation on my Windows 2000 DHCP server for the switch that I am autoinstalling. After many failures whereby the switch would not assign itself the IP I had reserved for it I discovered why.

The base MAC address of the switch (which incidentally is 00:11:21:EB:D3:C0) as confirmed by the label on the back and the switch startup screen was not the one being seen by the Windows 2000 DHCP server. Instead the MAC (or as Windows calls it the "UniqueID") is a 48 character string.

I attach a screenshot, the switch is the top one in the list, the other ones are regular PC hosts who show their MAC address.

I need to be able to work out in advance what a Cisco 2950's switch MAC (or UniqueID) is going to be to allow me to create a reservation for it.

Thanks in advance,

Ellis Dixon


Re: Really long MAC address?

Hi Ellis,

Can you restart your switch and then check on the DHCP serber which unique id it is showing.



New Member

Re: Really long MAC address?

It shows the same, so the UniqueID/MAC is static between reboots.

This is necessary for the reservation to function correctly, in that the switch is sent the same DHCP options (66 & 67) upon a restart without a config file present.



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