TABLE OF CONTENTS In version 7.0, Cisco introduces support for IP version 6. This is good news, as the demise (exhaustion) of the IP version 4 address space has been predicted and anticipated for several decades now. Before we delve into configuration of IPv6 on the PIX, we need to review IPv6 addresses. Although 32 bits of address space originally were thought to be more than enough, time and growth haven t proved this not to be the case. Additionally, IPv4 suffers from a lack of hierarchical structure; although addresses may be sequentially allocated and summarized, they are not optimized by routing or allocation.
Designers of IPv6 worked diligently to ensure that the same issues would not be encountered with version 6 of IP, by specifically addressing each of these issues. Members of the Internet community who were responsible for developing the protocol carefully scrutinized each new Request for Comments (RFC) penned for IP. In this section, we will cover IP version 6, which was developed to overcome the exhaustion of IPv4 addresses and to improve on IPv4 in general.
IPv6 eases the network administrator s burden in that Aggregatable Global Unicast (to be discussed later) addresses do not require translation when used to access external networks such as the Internet. In IPv4, private address spaces are used when global addresses are unavailable. These private addresses must be translated to a limited set of global addresses when accessing external networks. IPv4 address translation schemes include Network Address Translation...
