Windows DHCP Server : The unique Identifier you have entered may not be correct

By | December 15, 2012

Using the Windows DHCP server, you might noticed this message trying to do an IP reservation with the MAC address on your DHCP scope :

The unique Identifier you have entered may not be correct. Do you want to use this Identifier anyway?

And then :

The DHCP server received a message from a client that is not valid.

This is because you’ve entered the MAC address with colon ” : “

EXAMPLE

Instead of :

You must enter it like this :