为什么 yahoo 的权威 DNS 服务器会保留 stackoverflow 的 IP？还是我的本地 DNS 服务器缓存了 stackoverflow 的 IP？（如此处所述 - 第一个 DNS（1/2）缓存了 IP，因此它根本不会联系其他 DNS 服务器？）我如何“强制”我的 PC 向 ns3.yahoo.com 询问特定 IP，而不会从任何缓存中获取答案？谢谢！
答案1
不确定你是如何得到这个答案的，至少在 Windows 7 上我得到了这个：
C:\Users\dude> nslookup stackoverflow.com ns3.yahoo.com
Server: ns3.yahoo.com
Address: 203.84.221.53
*** ns3.yahoo.com can't find stackoverflow.com: Query refused
C:\Users\dude>
尝试以交互方式运行 nslookup，打开调试选项以查看它真正要求的是什么...在这里我看到我只是拒绝使用本地搜索列表和 IPv4 和 IPv6 地址的每种变体。 我怀疑您在本地主机表中有一个“stackoverflow.com”的条目，或者您正在访问 ns3.yahoo.com 的“特殊”镜像，该镜像允许对您的源地址空间进行递归查询。
C:\Users\dude> nslookup - ns3.yahoo.com
Default Server: ns3.yahoo.com
Address: 203.84.221.53
> set debug
> stackoverflow.com
Server: ns3.yahoo.com
Address: 203.84.221.53
------------
Got answer:
HEADER:
opcode = QUERY, id = 2, rcode = REFUSED
header flags: response, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0
QUESTIONS:
stackoverflow.com.localdomain.com, type = A, class = IN
------------
------------
Got answer:
HEADER:
opcode = QUERY, id = 3, rcode = REFUSED
header flags: response, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0
QUESTIONS:
stackoverflow.com.localdomain.com, type = AAAA, class = IN
------------
------------
Got answer:
HEADER:
opcode = QUERY, id = 4, rcode = REFUSED
header flags: response, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0
QUESTIONS:
stackoverflow.com, type = A, class = IN
------------
------------
Got answer:
HEADER:
opcode = QUERY, id = 5, rcode = REFUSED
header flags: response, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0
QUESTIONS:
stackoverflow.com, type = AAAA, class = IN
------------
*** ns3.yahoo.com can't find stackoverflow.com: Query refused
>