In this section we'll look at how you might provide infrastructure for two of the transition mechanisms that we discussed in Section 4.1. First we look at 6to4 Relay Routers. These might useful be deployed either by an ISP or at the border of a large organization that has a number of 6to4 users internally.
Second we'll look at the configuration of the KAME faith system. This is an implementation of TRT, and so we also cover a DNS server, totd, that can convert DNS A records into AAAA records.
We'll also look at how VLANs and other similar mechanisms can be used to provide IPv6 without disturbing existing IPv4 infrastructure.
We'd like to be able to describe good software to allow an ISP manage tunnels to their customers. Unfortunately, at the time of writing, we are not aware of any generally available software for doing this. It is possible that operation of such software is too ISP specific, probably requiring integration with billing systems and customer databases. One quick solution to this problem would be to become a POP for some tunnel broker service such as http://www.sixxs.net/.
We'll talk about the more service-oriented transition mechanisms, application proxies and port forwarding in particular, in Chapter 7.
Setting up a 6to4 relay router is actually quite a good way for an ISP to begin offering IPv6 services. Currently if an ISP's customers use 6to4 as a way to experiment with IPv6, their traffic may travel around the world ...