The book covers the patches to postfix for IPv6 support. However, postfix 2.2 is now here and supports IPv6 (and TLS) without the need for any patches. I upgraded a mail system using postfix over the weekend and found the process remarkably painless. Having read the IPV6_README file that came with postfix I discovered that I really only needed to make one change to main.cf, which was to tell postfix to listen on any inet protocol by using the directive inet_protocols = all.
The new IPv6 code even spotted a mistake in my original configuration file and logged a helpful error message: fatal: non-null host address bits in "2001:db8:ee0:cc01::/48", perhaps you should use "2001:db8:ee0::/48" instead! Seems to have been a nice integration of the work of Dean Strik and others into the Postfix mainline.
So, the RFC for “Unique Local IPv6 Unicast Addressing” has finally shown up as RFC 4193. These addresses are intended to cover some of the ground originally provided for by IPv6 site-local addressing. They also help out people who aren’t in a position to get IPv6 addresses from an ISP, maybe because they don’t have one.
The idea is to provide a large block of addresses that look global, are allocated randomly but that we all agree to not route globally. This means that they are cheap (generating random numbers is cheap), they are stable (because they don’t depend on your ISP), they work just like globals (so you don’t need to change your applications) and they can even be used site-to-site or when sites merge (because randomly allocating them is highly unlikely to produce collisions). However, because we do not know how to manage a routing table without aggregation, we can not route them globally.
Operationally, people won’t need to make many changes to support them. We’ll probably want to filter for these addresses at our site boundaries, and may want to make our recursive DNS servers authoritative for the reverse domain, in the same way people should answer for 10.in-addr.arpa if they use a subset of 10.0.0.0/8 for private addressing.
Ireland now has a National IPv6 Centre, which was launched on Friday. The centre has been set up to help support the IPv6 Task Force here and to provide a place that people can turn to if they need to know about IPv6. The Hamilton Institute, where I work, is involved as part of the consortium. The project is being lead by the good folk at TSSG. The industrial side of the action is covered by HEAnet and BT Ireland.