tl/dr: Here is a nice chart for you! I created the below chart a few years ago to post up for reference some of my coworkers would forget what our subnet mask was suppose to be. It didn't really work ...

Although IPv6 adoption seems to be moving at a snail's pace, there's no outrunning it. Brien Posey demystifies some of the addressing issues many admins are still trying to figure out. [Editor’s note: ...