v6 subnet size for DSL & leased line customers
Robert E. Seastrom
rs at seastrom.com
Fri Dec 28 02:50:01 UTC 2007
Leo Bicknell <bicknell at ufp.org> writes:
> In a message written on Thu, Dec 27, 2007 at 10:57:59PM +0100, Iljitsch van Beijnum wrote:
>> It is wih IPv6: you just connect the ethernet cable and the RAs take
>> care of the rest. _You_ _really_ _don't_ _need_ _DHCP_ _for_ _IPv6_.
>> If you need extreme control then manual configuration will give you
>> that, which may be appropriate in some cases, such as servers.
> Really. I didn't know RA's could:
> - Configure NTP servers for me.
> - Tell me where to netboot from.
> - Enter dynamic DNS entries in the DNS tree for me.
> - Tell me my domain name.
> - Tell me the VLAN to use for IP Telephony.
> Those are things I use on a regular basis I'd really rather not
> manually configure.
I'm running (native) IPv6 at home, and in the colo too. Most of my
ssh sessions to personally owned machines go over v6.
My laptops (with a single exception) are Macs. You may not be aware
that the Mac is fairly smart about which interface it uses for
connections - it will prefer the gigabit ethernet to the wireless when
it sees link... it prefers wireless to dialup too. Basically,
whenever you establish a new outgoing session it will use the "lowest
cost" interface to do the deed.
For IPv4, I have the same address manually assigned on the DHCP server
to both the gigabit ethernet's MAC address and the wireless
interface's MAC address. This means that when I plug into the gige,
as I do for filesharing or backing some files up, the Mac uses the
gigabit ethernet. When I unplug and carry the Mac to the conference
room, *all existing upper layer sessions are preserved* - TCP and
friends are blissfully unaware that a change has taken place; one
gratuitous arp so the router knows where to send the packets and we're
on our way again with nary a hiccup. I don't have an ssh session
croak just because I connected or disconnected a cable.
I'd really, really, really like to have DHCP6 on the Mac. Autoconfig
is not sufficient for this task unless there is some kind of trick you
can do to make the eui-64 come out the same for both interfaces (don't
Anyone from Apple reading this list? :-)
More information about the NANOG