IPv6 support for com/net zones on October 19, 2004

Joe Abley jabley at isc.org
Wed Oct 27 20:01:45 UTC 2004

On 27 Oct 2004, at 15:43, Daniel Roesen wrote:

> On Wed, Oct 27, 2004 at 03:21:44PM -0400, Joe Abley wrote:
>> Maybe Verisign needs more (reliable) v6 transit.
> Something is broken in several colors here. I'm seeing AS_PATHs
> like 6830 6175 109 7018 26415 (Sprint, Cisco, AT&T, Verisign) but
> a traceroute is going straight from 6830 to AT&T and dying there
> with !P.
> That you have no route for A is most probably a filtering issue
> somewhere... I'm seeing it being propagated by Sprint.

Since I mailed that, 3557 started receiving a covering /48 for A. Maybe 
there's some operational/maintenance-induced stability issues for those 

We've had reports before of F's covering /48 (2001:500::/48) being 
filtered by some people, based on the conviction that /48s were always 
bad and should never be accepted by anybody. It's possible that this is 
biting Verisign, too.

For the record, ARIN assign critical-infrastructure /48s which it is 
important to accept:


Gert Döring maintains an excellent summary of current good practice for 
v6 filtering (including cisco and JUNOS configuration examples, and 
filters of various degrees of strictness) here:


Operators who are currently blocking any prefix covered by 2001::/16 
which is longer than 32 bits are encouraged to review that page, and 
fix their routers.


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