[ipxe-devel] [PATCH 4/7] ipv6: Allow manual network configuration

[Hannes Reinecke]

On 04/24/2015 07:09 PM, Michael Brown wrote:
> On 01/04/15 08:26, Hannes Reinecke wrote:
>> Not on every system IPv6 autoconfiguration is working properly,
>> so allow for manual network configuration here.
>> Note: this configures the global route only. Link-local routes
>> are configured automatically.
> 
> I like the idea of being able to configure an IPv6 address manually.
> The major reason that I didn't already implement this is that having
> ${ip6} etc creates an expectation that the user should be able to
> retrieve the autoconfigured IPv6 addresses via these settings, as
> can be done for IPv4.
> 
> The difficulty then is that IPv6 allows for multiple addresses per
> interface, so we would need some sensible syntax to allow for access
> to the multiple addresses (or accept that only one address could be
> retrieved in this way, in which case the question becomes which
> address it is).
> 
Weeellll ... even IPv4 allows you to set multiple addresses.
Even nowadays. It's just a seldom-used feature :-)

For IPv6 we typically have 3 different address-classes:
link-local addresses, global dynamic addresses, and global static
addresses.
There rarely is any benefit from setting the link-local address;
so I'd disregard modifying _that_.
And one could argue that dynamic addresses are in fact assigned
from the outside, so we shouldn't be touching them, too.
With that reasoning we could just have a impose a restriction of
_one_ global static address, and the 'ipv6' mechanism would
allow you to modify that address only.

So with that restriction in place we'd be pretty similar to the
current ipv4 handling while retaining the most important feature
from IPv6, right?
True, we won't be able to modify the dynamic addresses, but
they'll be gone eventually, what with them having a timeout and all :-)

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		               zSeries & Storage
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