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

Christopher Morrow morrowc.lists at gmail.com
Mon Feb 9 20:20:37 CST 2009


On Mon, Feb 9, 2009 at 6:16 PM, Ricky Beam <jfbeam at gmail.com> wrote:
> On Fri, 06 Feb 2009 09:39:01 -0500, Iljitsch van Beijnum
> <iljitsch at muada.com> wrote:
>>>
>>> If you want the machine to always have the same address, either enter it
>>> manually or set your DHCP server to always give it the same address.
>>
>> Manual configuration doesn't scale. With IPv4, it's quite hard to make
>> this work with DHCP, but mostly because of a lack of IPv4 addresses. With

'quite hard to make this work'?? what?? have you been making a dhcp
server from scratch all these years? Iljitsch, what parts of making
static mappings in DHCP, or setting the configuration bits required
for dns/default-router/tftp-server/root-partition/wins-server/..... is
'hard to do' in a dhcp server with decently wide use today? (isc
dhcpd/windows-dhcp-server)

>> 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.

Why are you filling the discussion with FUD about dhcp servers??

>
> As I read it, you don't want to use DHCP because "it's an other service to
> fail."  Well, what do you think is broadcasting RA's?  My DHCP servers have
> proven far more stable than my routers. (and one of them is a windows server
> :-))  Most dhcp clients that keep any state will continue using the
> previously assigned address if the server is unavailable (and nothing else
> is using it.)  Configuring a static address in a DHCP server is a pretty
> trivial task.

thank you Mr. Beam.

>> 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?

>> very many people _want_ it and some people do in fact need it. I have no
>> problem with that, as long as it doesn't lead to the situation where I have
>> to run it.

no, you don't today have to run it... but why are you arguing against
the fact that admins at enterprises and ISP's have been making this
very clear argument for equal functionality to what's available today?

-Chris




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