Excel 2007 : compare IP addresses on multiple sheets for duplicates

Hello all,

I have been trying to figure out how to compare ip addresses on multiple different sheets for duplicates. I don't know the best way to do this so it would be great if I could get some help. I have attached the current excel spreadsheet for you. I would like to be able to have the system highlight any current duplicates I might have and also in the future when adding an IP address it will give some kind of indication that the number already exsists on another sheet.

Any help would be greatly appericated

Patrick