[TriLUG] IPv6 Networking on CentOS (RHEL)

[Seva Adari]

On Fri, Dec 23, 2011 at 4:36 PM, Randy Barlow
<randy at electronsweatshop.com>wrote:

> On 12/22/2011 06:35 PM, Seva Adari wrote:
> > I am not able to wrap my head around the fact that an automatically
> > generated addressing system could be used as static addresses for
> > publishing services (via DNS).
>
> The addresses are the same for each host every time if you use
> autoconfiguration. The first 64 bits are handed to the host by the
> router advertisement daemon, and comprise the network address. The
> second 64 bits are determined by an algorithm that converts the MAC
> address into a 64 bit host address. The full address would be the
> combination of the network and host addresses for 128 bit goodness.
> Every time that host comes up on that network, it will always have the
> same address.
>
> The static part that I am referring to is, being able to advertise your
address. With ip4, there is a system in place and icann  manages ip4
address space and hands off the addresses so it is easy to setup the
routing tables. Your ISP gets few blocks of certain class and it is
responsible for managing its block. ISPs typically give customers either a
full class or CIDRs and they manage those. If I am given a.b.c.d ip, then I
can publish a number services on this and I am guaranteed by my ISP that it
is going to route all the packets bound to a.b.c.d to my network.

In case of IP6, host could be generating the same IP address consistently,
but the first 64bits part needs to be managed by some organization similar
to IP4 system for the inbound packets to be delivered to IP6 host. There
should be a guarantee that the 64bit part assigned to you is not assigned
to anyone else, in other words, it is not autogenerated rather managed
assignment. Managed in the same sense as ip4 address space management.

I suppose if I spend some time trying to setup the ip6, a lot of these
issues will get cleared and I will have a better understanding.