Almost every network engineer knows the classic IPv4 network assignments by heart: Class A through E, private address space, loopback, link-local, etc. However, when it comes to IPv6, many engineers still need to get a good grip on the various address blocks that have been allocated for these and other functions. As a study-aid for students attending the IP6FD courses that I teach (or just anybody with an interest in IPv6), I decided to compile the information from various RFCs into a chart that lists the major IPv6 blocks, their use, and the initial bit patterns associated with these blocks. Continue reading →