PTR records for v6 hosts

[Bjørn Mork]

Ron Broersma <ron at spawar.navy.mil> writes:

> We wrote a tool that regularly polls the routers, grabs the ARP and ND
> tables (using appropriate snmp MIBs), looks for all the global unicast
> IPv6 addresses in the list, and then using their MAC address we map to
> the associated IPv4 address, then use that to look up the IPv4 PTR
> record in DNS, then use that to build an IPv6 PTR record and use
> dynamic DNS update to update the zone (with various optimizations such
> as caching, garbage collection, etc).   That works well for us
> (dealing with thousands of v6 hosts on our net), although there are
> challenges with differences in how each vendor implements the v6 MIBs,
> and churn from those horrible privacy/temporary addresses [RFCs 3041,
> 4941] that that all Microsoft OS's enable by default).  This, of
> course, is assuming each host has some amount of IPv4 and IPv6
> activity, but in reality it works just fine over time.

Nice solution for dual stack hosts.  But how do you plan to support IPv6
only hosts?

And does anyone have a proposal that would fit an ISP environment? Lets
say you use DHCP-PD to delegate a prefix to a customer, who is in full
control of his own "residential gateway" so you can't look up his
neigbour table.  What do you do?

- Delegate the reverse zone to the customer?  Most won't have a clue
  what to do with it.
- Provide a DDNS solution for the customer and not care whether they use
  it or not?  Most won't use it.
- Set up an IPv6 "walldns" (to borrow terminology from DJB)?  I don't
  really see the point.  How is a pointer record like
  x20010db800000000021a73fffe502834.example.com better than just not
  having a pointer?




Bjørn