Oh yeah--That's right. 32 levels--Much worse than I said. I wrote up many of the issues with reverse dns about 1.5 years ago. I submitted it to the IETF, but there was no interest in publishing this information.
http://www.av8.net/draft-anderson-reverse-dns-status-01.txt The following example was taken from RFC3596: 4321:0:1:2:3:4:567:89ab would be b.a.9.8.7.6.5.0.4.0.0.0.3.0.0.0.2.0.0.0.1.0.0.0.0.0.0.0.1.2.3.4.IP6. ARPA. On Mon, 30 Jun 2008, Frederico A C Neves wrote: > Mr. Anderson, > > On Sat, Jun 28, 2008 at 05:36:04PM -0400, Dean Anderson wrote: > > A number of the points you raise have already been addressed. > > > > The IPV6 Reverse resolution question has been discussed at length in > > DNSEXT previously. In fact, it was proposed to remove reverse resolution > > entirely from IPV6 for just the reason Dr. Huang notes. A 128 bit IPV6 > > address is 16 octets. To perform reverse resolution requires traversing > > 16 levels of DNS tree. > > Not exactly. The reverse delegation is at the 4 bits boundary, so the > correct is 32 possible levels, but this possibility doesn't impose all > these levels. Half of the levels are unlikely to be used and the other > half you'll see normally the average of 3 to 4 as we see it today for > IPv4. The amount of delegations levels are driven by the IP > distributions layers (IANA-RIR-NIR-ISP), not by the address space. > > Fred > _______________________________________________ > DNSOP mailing list > DNSOP@ietf.org > https://www.ietf.org/mailman/listinfo/dnsop > > -- Av8 Internet Prepared to pay a premium for better service? www.av8.net faster, more reliable, better service 617 344 9000 _______________________________________________ DNSOP mailing list DNSOP@ietf.org https://www.ietf.org/mailman/listinfo/dnsop
