Every so often an IPv6 router is supposed to send out Router Advertisements saying what IPv6 range(s) should be used on this subnet allowing a host to autoconfigure itself by appending it's MAC address to the IPv6 address and using that. So it's kinda like a built in DHCP.

Some gotcha's

• You need to configure linux boxen to send RouterAdvertisements, either by running radvd(8) (Router Adverisement Dameon) or by using zebra(8) or the like.
• You don't want to DHCP routers, so if you forward packets you aren't allowed to auto configure yourself. Kinda makes sense.
• You don't want to DHCP servers, so machines that run services should be manually configured with an IP address, if they aren't, they will auto configure themselves an address.
• Router configuration doesn't send out DNS servers or anything like that. I guess you're supposed to use AnyCast, except I don't know of anyone doing AnyCast DNS serving.

Other than that, it means that desktop machines and the like just plugin and work, no configuration necessary. Very cool.

Here's a page about how to configure RouterAdvertisements on debian, (although it's not very Debian specific): http://people.debian.org/csmall/ipv6/setup.html

Don't worry about your IPv6 boxes having several IP addresses per Interface. IPv6 enabled box collect them like stamps.