v6 & DSL / Cable modems [was: Private use of non-RFC1918 IP space (IPv6-MW)]

Nathan Ward nanog at daork.net
Tue Feb 10 22:17:01 UTC 2009

On 10/02/2009, at 3:20 PM, Christopher Morrow wrote:

>>> IPv6 it's easier, but you're still limiting the uptime of your  
>>> system to
>>> that of the DHCPv6 server. Router advertisements is much more  
>>> robust.
> 'more robust'... except it doesnt' actually get a device into a usable
> state without admins walking around to each machine and poking at them
> randomly. if you have 5 machines that's cool, knock yourself out, if
> you have 5000 or 50000 you are in a completely different ballpark of
> work. DHCP servers do this today, the servers pass out all the
> relevant bits require for dynamic-addressed and static-addressed
> systems, they can be rebooted, moved, re-addressed, re-homed... all
> without the masses of clients stopping their work.

I believe you are mis-interpreting Iljitsch's comments.
I believe he is talking about SLAAC, you are talking about *no* DHCPv6.

The difference is, SLAAC can still use DHCPv6 to get configuration  
information. If the DHCPv6 server goes away when using SLAAC for  
addressing, configuration information is already there.

>>> I have a lot of problems with DHCP and most people don't _need_  
>>> it. Still,
> can you explain how 'most people don't need it'?? is that because most
> people have an admin to go configure their DNS servers in their
> resolver config?? Consumer Internet users are a great example of this,
> if necessary an ISP can pass out new DNS servers, and in 8-10 days
> easily remove the old DNS servers from the network, or move them to
> another place in the network seemlessly without having to touch each
> consumer device.
> Why would anyone NOT want that?? what replaces that option in current
> RA deployments?

Again, this seems to be confusion with SLAAC vs. "no DHCPv6 what so  
ever". I could be wrong though - I don't want to be putting words in  
to  Iljitsch's mouth.

Nathan Ward

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