IPv6 Implementation and CPE Behavior

Tue Jan 12 01:19:32 UTC 2016

> On Jan 11, 2016, at 1:37 PM, Owen DeLong <owen at delong.com> wrote:
> 
> 
>> On Jan 11, 2016, at 10:23 , James R Cutler <james.cutler at consultant.com> wrote:
>> 
>>> On Jan 11, 2016, at 12:01 PM, Graham Johnston <johnstong at westmancom.com> wrote:
>>> 
>>> Are most CPE devices generally not IPv6 capable in the first place?  For those that are capable are they usually still configured with IPv6 disabled, requiring the customer to enable it?  For those CPE that are capable and enabled, is there a common configuration such as full blown DHCPv6 with PD?
>> 
>> I can’t speak regarding “most CPE devices” but for CPE = Apple Airport Extreme
>> 
>> 	• At least since the AirPort Extreme 802.11n (AirPort5,117) was released in 2011, the hardware has supported native IPv6 routing and acceptance of PD from the WAN.
>> 
>> 	• The default configuration for firmware 7.7.3 is automatic WAN IPv6 configuration, native IPv6 routing, and, acceptance of PD from the WAN. End systems on the single LAN receive a /64.
> 
> To be more clear… The LAN receives a /64 from which end systems are able to construct one or more end system addresses using SLAAC.

I tried to keep it simple - my original draft said “All end systems on the LAN receive the same /64 prefix in RAs, even if the ISP has delegated a /56, for example.  It was altogether too wordy so I excised about half of the original text. Maybe I went too far.

> 
>> 
>> 	• No DHCPv6 is provided to the LAN through firmware up to the current version 7.7.3. 
>> 
> 
> The good news is that RDNSS is allegedly supported in recent firmware releases.

I have found no documentation from Apple or in the Airport Utility GUI that mentions it. I have figured out some of IPv6 entries in .baseconfig files, but none for RDNSS.

The bad news is that I have yet to really understand RDNSS in the context of OS X. I don’t find any recognizable mention in sysctl inet6 parameters. OS X El Capitan systems autoconfigure the LAN/64:EUI-64 address of the Airport Extreme along with the IPv4 nnn.nnn.nnn..1 address as DNS server  addresses.  Windows 10 appears to do the same. (I haven’t bothered to look into Windows internals.  I don’t get paid to do that anymore.) I keep IPv6 disabled on my Snow Leopard Server instances, both because no IPv6 DNS server address is ever autoconfigured and because none of those instances should ever get incoming IPv6 traffic.
> 
> Owen

Thanks for your comments.

James R. Cutler
James.cutler at consultant.com
PGP keys at http://pgp.mit.edu