IPv6 Address assignment
More and more server providers offer IPv6. The question is how to assign an address to a customer? With IPv6 there are several ways:
SLAC – StateLess Auto Configuration is a realy nice But there are some drawbacks:
1. IPv6 is might be enabled on a lot of host without the user knowing about it. Now consider Joe Looser, who was barely able to setup Linux on his server and who had a hard time securing his box with iptables (by putting together bits and pieces found on the net without realy knowing what these bits and peaces are realy doing[1].). By announcing prefixes you just enabled a nice backdoor into Joe’s server.
2. If hardware is replaced, a server will get a new IPv6 address. The user then has to change at least his DNS configuration, probably much more (MTA, MDA, monitoring, packet filter, …)
3. Moving all customers who want IPv6 into a different VLAN might be an option but this will require changes in your IPv4 setup.
DHCPv6 – The way to go in the IPv4 world. Unfortunately there is no (default) way to configure a MAC – IPv6 address binding[2]. This way, if the hardware changes the user gets a new IPv6 address. The same problems as with SLAC apply.
Manual configuration – For me the best way to go right now. Everybody who want’s to run IPv6 should be able to do this and it only takes a minute or two.
[1] I was told that this is not very uncommon.
[2] At least none that I know of.
