On Mon, Jun 18, 2018 at 4:28 PM, Job Snijders <job@ntt.net> wrote:

Dear working group,

Feedback welcome - should 2002::/16 still be accepted in the DFZ?

Kind regards.

Job

---------- Forwarded message ---------
From: Job Snijders <job@ntt.net>
Date: Mon, 18 Jun 2018 at 23:08
Subject: Time to add 2002::/16 to bogon filters?
To: NANOG [nanog@nanog.org] <nanog@nanog.org>

Dear all,

TL;DR: Perhaps it is time to add 2002::/16 to our EBGP bogon filters?

It is kind of strange that in the default-free zone (where we don’t announce defaults to each other) - we will propagate what is effectively an IPv4 default-route, in the IPv6 DFZ. 

IETF has politely abandoned the prefix: 

https://tools.ietf.org/html/rfc7526

RFC7526 most certainly does not deprecate or abandon the prefix 2002::/16.

From Section 4 of RFC7526;

    This document formally deprecates the anycast 6to4 transition mechanism defined in [RFC3068] and the associated anycast IPv4 address 192.88.99.1.
    ...
    The basic unicast 6to4 mechanism defined in [RFC3056] and the associated 6to4 IPv6 prefix 2002::/16 are not deprecated.

Wes George highlighted operational problems from accepting 2002::/16 on the data-plane slide 6: 

http://iepg.org/2018-03-18-ietf101/wes.pdf

Is there still really any legit reason left to accept, or propagate, 2002::/16 on EBGP sessions in the DFZ?

Section 6 of RFC7526 has several recommendations, filtering 2002::/16 is not generally one of them. However, if your customers are not using 6to4 at all, then filtering 2002::/16 probably won't hurt anything. But that is not the same thing as saying that 2002::/16 is a bogon in all situations, and that is not supported by RFC7526.  If you have other data to support bogonising 2002::/16 I'm happy to listen.
 

Kind regards,

Job