我们知道DNS的工作方式是递归地检索域的后缀。例如,对于www.google.com,它会检索com的名称服务器并获得其IP地址,然后使用该名称服务器检索google.com...
获取名称服务器的IP地址是这个过程中的关键部分。如果我们执行dig google.com,这就是结果。
We can see from this code snippet that the IP addresses for Google.com are listed in the ANSWER SECTION and the nameservers are listed in the AUTHORITY SECTION of the response. The IP address for ns2.google.com is also included in the ADDITIONAL SECTION. However, if we use the "dig com" command, we receive a different response.
获取名称服务器的IP地址是这个过程中的关键部分。如果我们执行dig google.com,这就是结果。
We can see from this code snippet that the IP addresses for Google.com are listed in the ANSWER SECTION and the nameservers are listed in the AUTHORITY SECTION of the response. The IP address for ns2.google.com is also included in the ADDITIONAL SECTION. However, if we use the "dig com" command, we receive a different response.
; <<>> DiG 9.6.0-APPLE-P2 <<>> com. ;; 全局选项: +cmd ;; 收到回答: ;; ->>报头<<- 操作码: 查询, 状态: NOERROR, ID: 50809 ;; 标志: qr rd ra; 查询: 1, 回答: 0, 授权服务器: 1, 附加信息: 0
;; 问题部分: ;com. IN A
;; 授权部分: com. 900 IN SOA a.gtld-servers.net. nstld.verisign-grs.com. > 1369263918 1800 900 604800 86400
;; 查询时间: 17 毫秒 ;; 服务器: ..*.#53(.*..) ;; 当: Wed May 22 16:05:48 2013 ;; 消息大小 rcvd: 94
这段代码中并没有显示com域名服务器的IP地址。那么我的问题是,递归器如何知道TLD域名服务器(如,com)的IP地址?
ANY
- user.dz