NS查找链在哪里停止？

一般来说，NSlogging是以胶水的forms存储的。 所以，当你去a.com你去根（* .root-servers.net），这是硬编码到您的DNS服务器。 在.com的情况下，您可以指向* .gtld-servers.net，其托pipe.com tld。 从那里你会得到NSlogging与IP地址的a.com由于胶水logging。 这里是一个寻找谷歌的例子..

  [~] dig +trace google.com ; <<>> DiG 9.7.3 <<>> +trace google.com ;; global options: +cmd . 321319 IN NS k.root-servers.net. . 321319 IN NS c.root-servers.net. . 321319 IN NS l.root-servers.net. . 321319 IN NS g.root-servers.net. . 321319 IN NS j.root-servers.net. . 321319 IN NS f.root-servers.net. . 321319 IN NS d.root-servers.net. . 321319 IN NS h.root-servers.net. . 321319 IN NS a.root-servers.net. . 321319 IN NS m.root-servers.net. . 321319 IN NS e.root-servers.net. . 321319 IN NS b.root-servers.net. . 321319 IN NS i.root-servers.net. ;; Received 512 bytes from 10.10.0.1#53(10.10.0.1) in 7 ms com. 172800 IN NS g.gtld-servers.net. com. 172800 IN NS m.gtld-servers.net. com. 172800 IN NS a.gtld-servers.net. com. 172800 IN NS f.gtld-servers.net. com. 172800 IN NS b.gtld-servers.net. com. 172800 IN NS i.gtld-servers.net. com. 172800 IN NS h.gtld-servers.net. com. 172800 IN NS k.gtld-servers.net. com. 172800 IN NS e.gtld-servers.net. com. 172800 IN NS l.gtld-servers.net. com. 172800 IN NS d.gtld-servers.net. com. 172800 IN NS j.gtld-servers.net. com. 172800 IN NS c.gtld-servers.net. ;; Received 488 bytes from 192.5.5.241#53(f.root-servers.net) in 35 ms google.com. 172800 IN NS ns2.google.com. google.com. 172800 IN NS ns1.google.com. google.com. 172800 IN NS ns3.google.com. google.com. 172800 IN NS ns4.google.com. ;; Received 164 bytes from 192.26.92.30#53(c.gtld-servers.net) in 40 ms google.com. 300 IN A 72.14.204.105 google.com. 300 IN A 72.14.204.103 google.com. 300 IN A 72.14.204.99 google.com. 300 IN A 72.14.204.147 google.com. 300 IN A 72.14.204.104 ;; Received 108 bytes from 216.239.36.10#53(ns3.google.com) in 124 ms 

ns3.google.com的地址是从附加部分返回的gtld-server获得的。

 [~] dig @c.gtld-servers.net ns3.google.com ; <<>> DiG 9.7.3 <<>> @c.gtld-servers.net ns3.google.com ; (1 server found) ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 62420 ;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 4, ADDITIONAL: 4 ;; WARNING: recursion requested but not available ;; QUESTION SECTION: ;ns3.google.com. IN A ;; AUTHORITY SECTION: google.com. 172800 IN NS ns2.google.com. google.com. 172800 IN NS ns1.google.com. google.com. 172800 IN NS ns3.google.com. google.com. 172800 IN NS ns4.google.com. ;; ADDITIONAL SECTION: ns2.google.com. 172800 IN A 216.239.34.10 ns1.google.com. 172800 IN A 216.239.32.10 ns3.google.com. 172800 IN A 216.239.36.10 ns4.google.com. 172800 IN A 216.239.38.10 ;; Query time: 44 msec ;; SERVER: 192.26.92.30#53(192.26.92.30) ;; WHEN: Sat Sep 24 10:04:56 2011 ;; MSG SIZE rcvd: 164