1. DNS/返答/referral
Contents
2. 参照返答
DNS問合せに対する５種類の返答(DNS/返答/DJBの分類)のうちのひとつである。
DNS/返答/delegation を示すためにも使われる。
安全のためには、リゾルバーはdelegationではないreferral返答は無視すべきだ。../参照返答
- 当初は毒盛の危険性は想定されていなかった）
3. 形
Answer Sectionにレコードはなくて、Authority SectionにNSが含まれている。
A referral (a list of two or more name servers and IP addresses tha are closer the next level down in the name hierarchy to the requested domain ...
http://www.rfc-editor.org/rfc/rfc2308.txt sections 2.1 and 2.2
http://www.tech-faq.com/understanding-dns-queries-and-lookups.html
Referral answer: A referral response is returned if the DNS server does not support recursion. A referral contains additional resource records for resolving the request.
RFC1034 2章より
- Clients of the domain system should be able to identify
trusted name servers they prefer to use before accepting
referrals to name servers outside of this 'trusted' set.きちんと定義されているのだろうか。(DNSが作られた目的と背景をよく考えてみよう。）
- 名前解決のための助け合いの活動だったような印象だ。（私は「知らないので、XXさんに聞いてみて」という感じ）
%grep -n -i -2 referral rfc1035.txt
148-resolver processes a user query it asks a known name server for the 149-information; in return, the resolver either receives the desired 150:information or a referral to another name server. Using these 151:referrals, resolvers learn the identities and contents of other name 152-servers. Resolvers are responsible for dealing with the distribution of 153-the domain space and dealing with the effects of name server failure by -- 968- 969-NS records cause both the usual additional section processing to locate 970:a type A record, and, when used in a referral, a special search of the 971-zone in which they reside for glue information.
4. draft
Please See Below: Use Only Downward Referrals in the DNS
- draft-sullivan-dnsop-refer-down-00
https://tools.ietf.org/id/draft-sullivan-dnsop-refer-down-00.html