I've been battling a problem with IPv6. I have a static /56, but no matter what prefix length I request, I always get back a /60 (and always the same /60 each time). So if I request a /56, I get that /60. If I request a /57, or even a /64, I get the same /60. I've tried rebooting the modem, I've tried changing my DUID, I've tried changing the MAC of the interface that is making the request, I've tried using a different interface altogether.
Running some tcpdumps of the request and response show that I am requesting the /56 (I tried two different dhcpv6 PD clients), but what comes back is always the same /60.
The hardware in question is the Netgear CG3000DCR, hardware version 1.04, firmware V3.01.08.
Any suggestions for a next step would be hugely appreciated. There may be differences under the covers, but at least on the surface, my problem seems to match the one described here: http://forums.businesshelp.comcast.com/t5/IPV6/Static-IPV6-only-works-with-64-or-60-NOT-56/m-p/30522...
I had that same behavior....until I had my modem switched out to a Cisco last week. Now, no matter what I do, I can't even get a PD to my internal CPE (my modem is in what they call "passthrough" mode with a /29 of static space). I use IPv6 extensively and this has been a pretty big problem as I work as an engineer and need to be able to connect to things via v6 for testing - I have a ticket open to hopefully fix this. ...but I digress.
As far as the hint, that will always be overridden by whatever the dhcp server or dhcp service is configured to hand out. You can ask for a /48 and DHCP will always hand out what it is both configured to hand out and what it has in its lease file.
...Hit post too soon. It's worth calling business support. I had to get passed around but found someone that knew v6 and was willing to work my problem up the chain (hopefully). They got it escalated this afternoon. You shold call and ask about using more of your /56, I'm actually curious myself. I only use 3 of the /64 out of the /60 that I used to get delegated.
Thanks. I did call business support (ultimately it became several calls over the past couple of days), with... mixed results. Frustrating. I did finally manage to get to L2 support, so I have some hopes for the most recent call, though.