unreach problems

Bernhard Schmidt berni at birkenwald.de
Fri Oct 20 14:43:23 CEST 2006

Paul Cairney wrote:

>>> "NTT Communications accepts /19 through /32, and /35 from 2001::/16 (global unicast allocations)"
>>> They seem to be willing to accept shorter prefixes from customers however will advertise these on to customer but not their peers.
>> Which makes some sort of sense for deaggregates (for traffic engineering),
>> but doesn't make too much sense for official microallocations... :(
> Well their policy for ARIN's PI allocations seems ok.
> "NTT Communications accepts /44 through /48 from 2620::/23 (ARIN PI allocations)"
> However this obviously doesnt take into account allocations for dns servers..

I don't think their filtering is an issue here, the prefix used to work 
fine through 2914, see


Looks like an issue at UltraDNS to me. Their second micro-allocation 
nameserver (nsd.nic.uk, 2001:502:100e::/48) works fine through Verio btw.

Do we have someone from UltraDNS/Verio on this list?


More information about the ipv6-ops mailing list