dhcpcd-discuss

On 02/06/2016 21:29, Neal P. Murphy wrote:
> On Wed, 1 Jun 2016 19:18:46 -0400 "Neal P. Murphy"
> <neal.p.murphy@xxxxxxxxxxxx> wrote:
> 
>> ... I'm beginning to suspect Comcrash's servers because dhcpcd
>> seems to work flawlessly for a while, and then stops.
> 
> I'm dunno what to suspect now. It still wouldn't work right this
> afternoon. Should dhcpcd detect that the offered des. pref. is not
> the same size as requested and reject it?

Good question!
The RFC doesn't not say that it's an option to request a specific prefix
size, the guidance is it's more of a hint.
As such, dhcpcd will just use whatever the server gives and split it as
best it can.

> So next I generated new IAIDs and started from no 'old' /128 and
> ::/60 PD request. And it came right up with a new /128 but the old
> /60 it'd been giving me before.

/128 will be from IA_NA or IA_TA, not IA_PD.
Don't muddy the water here :)

> This time I will leave IPv6 running to see if (how long, really) it
> remains stable; see if renewal works. And add ::1 of the /60 to the
> internet IF; for some reason I get the idea that the /128 Comcrash
> gives me is needed only to route packets to any of those /60
> destinations. Oh, and polish the firewall some.

Yes no maybe.
I'm not an ISP, but the only reason to hand out a /128 IA_NA is if you
don't have IA_PD support. Saying that, technically you don't have to
assign an address to the router for the PD - it's just easier to do so
as it enabled rtadvd(8) on the BSD's (Linux has another equivalent) to
pickup the address an advertise that on the downstream interfaces.

Roy