I'm working through the CBT Nuggets video's for ICND1 and currently going through the subnetting. Working through practice sites, I'm getting a majority of the questions right, however I ran into one issue that I don't understand how the site is getting there, and even thought maybe they are wrong.(subnetting.net) The question was: How many Subnets and usable hosts can you have on a 172.26.00/20 network. Originally I answered 16 Subnets and 4064 hosts, which I now understand is wrong. (I was doing 16x254 taking 2 away from 256 for the subnet and network) The site however says the correct answer is 16 Subnets and 4096 hosts. How can you have 4096 usable hosts, when you can't be using the broadcast? While I can get to 4096 myself, I didn't think those would all be usable hosts, so this really through me off track. Is the site wrong, or maybe the wording used? Also, this thing about 256 Subnets, why do I keep seeing the number 256 used? I understand that counting subnets you will eventually hit 256, I just don't understand why it's used as in the above question since I thought it only went from 0-255. Even if you write out the chart there is no 256. Mask Value 128 | 192 | 224 | 240 | 248 | 252 | 254 | 255 Weights 128 | 64 | 32 | 16| 8 | 4 | 2 | 1 Thanks in advance for any guidance. Cheers.