Issues with Private IP Addressing in the Internet

The purpose of this document is to provide a discussion of the potential problems of using private, RFC 1918, or non-globally routable addressing within the core of a Service Provider (SP) network. The discussion focuses on link addresses and, to a small extent, loopback addresses. While many of the issues are well recognised within the ISP community, there appears to be no document that collectively describes the issues. This document is not an Internet Standards Track specification; it is published for informational purposes.