The Challenge of Managing an Address Space
Managing an address space is a deceptively difficult chore, particularly if you are using globally routable addresses. Do you remember the private addresses we looked at in Chapter 5, “The Date of Doom”? These were ranges of regular IP addresses that were arbitrarily reserved by the IETF in RFC 1918 for use in IP-based networks that didn't need Internet connectivity. IP might have been required to support an application base, but the fact that the network was not part of a larger internetwork meant that the addresses didn't have to be globally unique. If they don't have to be globally unique, they can't be routed on the Internet.
The private address blocks reserved in RFCs 1597 and 1918 are sometimes ...