不同DNS对于网络出口判定不一致导致解析结果不同

[FeeiCN]

部分域名会增加访问速度，会针对不同线路（电信、联通、移动、教育）解析不同IP，而不同DNS服务商对于网络出口的线路判定不一定准确，导致同一网络、同一域名下针对不同的DNS会出现不同的IP。

[FeeiCN]

阿里云DNS（223.5.5.5/223.6.6.6）和114.114.114.114在同一网络环境下同一域名(try.tuchong.com)解析出来的域名不一样。

绑定这两种不同的DNS都能访问，问题应该是出在对于当前网络出口（电信、联通、移动、教育）识别上。

➜  ESD git:(master) ✗ dig try.tuchong.com @223.5.5.5

; <<>> DiG 9.10.6 <<>> try.tuchong.com @223.5.5.5
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 9900
;; flags: qr rd ra; QUERY: 1, ANSWER: 16, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;try.tuchong.com.		IN	A

;; ANSWER SECTION:
try.tuchong.com.	15	IN	CNAME	all.tuchong.com.w.kunlunca.com.
all.tuchong.com.w.kunlunca.com.	15 IN	A	222.186.49.171
all.tuchong.com.w.kunlunca.com.	15 IN	A	58.218.203.138
all.tuchong.com.w.kunlunca.com.	15 IN	A	58.218.203.231
all.tuchong.com.w.kunlunca.com.	15 IN	A	180.101.150.30
all.tuchong.com.w.kunlunca.com.	15 IN	A	180.101.150.32
all.tuchong.com.w.kunlunca.com.	15 IN	A	222.186.49.166
all.tuchong.com.w.kunlunca.com.	15 IN	A	58.218.203.246
all.tuchong.com.w.kunlunca.com.	15 IN	A	222.186.49.168
all.tuchong.com.w.kunlunca.com.	15 IN	A	180.101.150.26
all.tuchong.com.w.kunlunca.com.	15 IN	A	180.101.150.29
all.tuchong.com.w.kunlunca.com.	15 IN	A	180.101.150.25
all.tuchong.com.w.kunlunca.com.	15 IN	A	58.218.203.228
all.tuchong.com.w.kunlunca.com.	15 IN	A	222.186.49.226
all.tuchong.com.w.kunlunca.com.	15 IN	A	58.218.203.226
all.tuchong.com.w.kunlunca.com.	15 IN	A	222.186.49.170

;; Query time: 21 msec
;; SERVER: 223.5.5.5#53(223.5.5.5)
;; WHEN: Wed Apr 18 11:36:17 CST 2018
;; MSG SIZE  rcvd: 314

➜  ESD git:(master) ✗ dig try.tuchong.com @114.114.114.114

; <<>> DiG 9.10.6 <<>> try.tuchong.com @114.114.114.114
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 61809
;; flags: qr rd ra; QUERY: 1, ANSWER: 7, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;try.tuchong.com.		IN	A

;; ANSWER SECTION:
try.tuchong.com.	14344	IN	CNAME	all.tuchong.com.w.kunlunca.com.
all.tuchong.com.w.kunlunca.com.	124 IN	A	180.163.155.11
all.tuchong.com.w.kunlunca.com.	124 IN	A	180.163.155.10
all.tuchong.com.w.kunlunca.com.	124 IN	A	180.163.155.12
all.tuchong.com.w.kunlunca.com.	124 IN	A	180.163.155.9
all.tuchong.com.w.kunlunca.com.	124 IN	A	180.163.155.7
all.tuchong.com.w.kunlunca.com.	124 IN	A	180.163.155.8

;; Query time: 75 msec
;; SERVER: 114.114.114.114#53(114.114.114.114)
;; WHEN: Wed Apr 18 11:34:31 CST 2018
;; MSG SIZE  rcvd: 181