= DNS/qname-minimisation/broken_CDN =

Query name minimization and authoritative DNS server behavior
  Shumon Huque, Verisign Labs
DNS-OARC 2015 Spring Workshop, Amsterdam, NetherlandsMay 9th 2015

https://indico.dns-oarc.net/event/21/contributions/298/attachments/267/487/qname-min.pdf
{{{
Cloudflare is aware of this defect and plans to fix it in the near future.
Update: April 2015 from Cloudflare. The problem has been fixed.
}}}

https://twitter.com/beyondDNS/status/916154514096324608

elb.amazonaws\.com　(NS) queryの結果ですね。
  noerror, nxdomain 返答が混在している。

調べ直してみたら、NXDOMAIN 返答はしなくなっている。いつからか。-- ToshinoriMaeno <<DateTime(2018-08-27T22:31:53+0900)>>


== debian ==
Re: DNS Qname minimisation
https://lists.debian.org/debian-project/2016/03/msg00044.html

There are serious potential operation issues with Qname minimization.
  よく読む必要がある。
-- ToshinoriMaeno <<DateTime(2017-06-11T13:48:38+0900)>>

akamai, awsdns, cloudflare などがあげられていたが、現在は修正されたようだ。-- ToshinoriMaeno <<DateTime(2018-08-27T22:08:19+0900)>>

{{{
There is a workaround available for the broken-CDN issue: on the first
NXDOMAIN reply from an intermediary (Qname minimized) query, you disable
Qname minimization entirely and do the full query.  This opens up Qname
minimization to attacks that "disable it" by triggering this workaround
and forcing a full query.

Worse, if this workaround is the only way for a future DNS application
to signal Qname minimization resolvers to query the full name on a deep
chain (see below), it *will* get used (and/or abused) for that,
effectively redefining what NXDOMAIN means in practice, and not in a
helpful way.  This is not a good thing for DNS operations and future
scalability, at all.
}}}

IPv6 reverse-zone では amplificationの心配がある。(deep-chain issue)


{{{
Shumon Huque, Verisign Labs
DNS-OARC 2015 Spring Workshop, Amsterdam, Netherlands
May 9th 2015

Query name minimization and authoritative DNS server behavior
}}}
https://indico.dns-oarc.net/event/21/contribution/9/material/slides/0.pdf