Some of the guys from the KAME project have written a book on the KAME IPv6 implementation. This should be quite an interesting read for anyone who wants to understand how you’d write an IPv6 stack, as the KAME stack has been one of the important reference IPv6 stacks that have been available during the development of IPv6. Each chapter contains a code walk-through, written in a similar style to Steven’s TCP/IP Illustrated Volume II.
While reconfiguring a Linux gateway recently I managed to get it into a rather confused state, where it thought that its own addresses were unreachable. Attepmting to ping it produced this ICMP message.
20:18:04.441662 2001:770:11d::3 > 2001:770:11d:0:20d:56ff:fe22:320c: icmp6: 2001:770:11d::3 unreachable address
ICMP is usually a pretty dry protocol - I think this is about as funny as ICMP messages come!