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本帖最后由 llzqq 于 2010-06-01 15:44 编辑
C:\Documents and Settings\Administrator>dig lb.libapay.com
; <<>> DiG 9.3.3 <<>> lb.libapay.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 846
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 0
;; QUESTION SECTION:
;lb.libapay.com. IN A
;; ANSWER SECTION:
lb.libapay.com. 30 IN A 61.152.161.122
;; AUTHORITY SECTION:
lb.libapay.com. 600 IN NS ns1.lb.libapay.com.
lb.libapay.com. 600 IN NS ns2.lb.libapay.com.
;; Query time: 375 msec
;; SERVER: 202.99.166.4#53(202.99.166.4)
;; WHEN: Tue Jun 01 15:32:04 2010
;; MSG SIZE rcvd: 84
概括起来有两点值得注意:
1. 权威DNS上A记录与NS记录的TTL取值太小!各地缓存DNS要分钟都要到权威DNS上取数据,如遇网络不畅则大大增加无法解析的概率。
2. 权威DNS服务器的托管线路不好,网络延时过大。会经常导致查询超时而失败!
补充:
C:\Documents and Settings\Administrator>dig @ns1.lb.libapay.com libapay.com ns
; <<>> DiG 9.3.3 <<>> @ns1.lb.libapay.com libapay.com ns
; (1 server found)
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 997
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;libapay.com. IN NS
;; Query time: 93 msec
;; SERVER: 61.152.161.120#53(61.152.161.120)
;; WHEN: Tue Jun 01 15:39:57 2010
;; MSG SIZE rcvd: 29
C:\Documents and Settings\Administrator>dig @ns2.lb.libapay.com libapay.com ns
; <<>> DiG 9.3.3 <<>> @ns2.lb.libapay.com libapay.com ns
; (1 server found)
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 743
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;libapay.com. IN NS
;; Query time: 62 msec
;; SERVER: 210.13.74.189#53(210.13.74.189)
;; WHEN: Tue Jun 01 15:40:03 2010
;; MSG SIZE rcvd: 29
权威DNS少了NS记录项,虽然理论上不加也能工作,但强烈建议加上NS,即:
@ 2D IN NS ns1.lb.libapay.com
@ 2D IN NS ns2.lb.libapay.com |
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