Cisco IOS Wildcard mask
From Teknologisk videncenter
Terry Slattery CCIE#1026 (The fist one to pass a CCIE exam)[1]: "I had to jump in on the wildcard mask topic, because the idea of inverting the subnet mask has been around since the early days of Cisco training. I asked Kirk Lougheed, one of Cisco’s founders and the principal software developer at the begining, about why the wildcard mask uses the bits it does (i.e. 1 = don’t care). He told me that it was just a decision he made one day and that it could have gone either way."