Chapter 7. Services
A satisfied customer; we should have him stuffed.
In this chapter, we talk about commonly deployed network services, and how they can be configured and offered over IPv6. We have assume a basic familiarity with the services and software discussed, and focus on issues relating to IPv6 deployment.
Most of the higher level protocols that you are familiar with can theoretically be transported over IPv6 with almost no modification. All that’s generally required is that the clients and servers be modified to make and accept IPv6 connections rather than IPv4. A good example of this is NNTP: many people are now taking Usenet news feeds over IPv6 as a way to move some bulk traffic from IPv4 to IPv6 while having a minimal impact on customers.
Unfortunately, there are some exceptions to the general case. Some of these exceptions
are minor “layering violations” and do not greatly affecting the
rewriting of a given application to support IPv6. For example, the
Received: header in SMTP can
mention the IPv4 address of the host mail was received from, such as
[127.0.0.1]. Clearly, this needs
only minor changes to operate over IPv6: mail received from the IPv6
localhost would be denoted
[IPv6:::1]  instead. More serious problems arise when IPv4 addresses are a semantic part of the protocol itself. Here addresses may be embedded within the protocol to be later interpreted by the other communicants as, perhaps, a message indicating where a connection ...