1. DNS/実装/cloudflare

存在しない名前に対して、

• NXDOMAINではなく、noerror(NoName)を返す。

https://github.com/kubernetes/dns/issues/119

With Wireshark, I was able to determine that Cloudflare's NS returns RCODE = 0 with no RRs 
when queried with a nonexistent domain (e.g. www.yahoo.com.mydomain.com). 
Most other NSs I've tried return RCODE = 3 in this case.
 (This issue never came up until I moved to Cloudflare; my domain registry's nameservers return RCODE = 3 for nonexistent domains.)

/返事

anyには答えないので、typeを変えて探す。:-<

1.1. history xxi.jp

xxi.jp は登録抹消

%dnsq ns xxi.jp a.dns.jp

2 xxi.jp:
83 bytes, 1+0+2+0 records, response, noerror
query: 2 xxi.jp
authority: xxi.jp 86400 NS austin.ns.cloudflare.com
authority: xxi.jp 86400 NS bonnie.ns.cloudflare.com

%dnsq ns qmail.xxi.jp austin.ns.cloudflare.com

2 qmail.xxi.jp:
94 bytes, 1+0+1+0 records, response, authoritative, noerror
query: 2 qmail.xxi.jp
authority: xxi.jp 3600 SOA austin.ns.cloudflare.com dns.cloudflare.com 2024176943 10000 2400 604800 3600

%dnsq any qmail.xxi.jp austin.ns.cloudflare.com

255 qmail.xxi.jp:
88 bytes, 1+1+0+0 records, response, authoritative, noerror
query: 255 qmail.xxi.jp
answer: qmail.xxi.jp 3789 13 \015ANY\040obsoleted\037See\040draft-ietf-dnsop-refuse-any

%dnsq any qmail.xxi.jp austin.ns.cloudflare.com

255 qmail.xxi.jp:
88 bytes, 1+1+0+0 records, response, authoritative, noerror
query: 255 qmail.xxi.jp
answer: qmail.xxi.jp 3789 13 \015ANY\040obsoleted\037See\040draft-ietf-dnsop-refuse-any

1.2. wildcard Aはない

$ dnsq a \*.xxi.jp austin.ns.cloudflare.com
1 \052.xxi.jp:
90 bytes, 1+0+1+0 records, response, authoritative, noerror
query: 1 \052.xxi.jp
authority: xxi.jp 3600 SOA austin.ns.cloudflare.com dns.cloudflare.com 2025391413 10000 2400 604800 3600

1.3. MX があった

$ dnsq mx \*.xxi.jp austin.ns.cloudflare.com
15 \052.xxi.jp:
77 bytes, 1+2+0+0 records, response, authoritative, noerror
query: 15 \052.xxi.jp
answer: \052.xxi.jp 300 MX 10 mxa.mailgun.org
answer: \052.xxi.jp 300 MX 10 mxb.mailgun.org

だが、MXのないものがほとんどだ。