Правильно так:
Сначала узнаем текущие корневые (вообще список меняется редко, но мало ли):
inkvizitor68sl@isera:~$ host -v -t NS .
Trying "."
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 34596
;; flags: qr rd ra; QUERY: 1, ANSWER: 13, AUTHORITY: 0, ADDITIONAL: 13
;; QUESTION SECTION:
;. IN NS
;; ANSWER SECTION:
. 190148 IN NS k.root-servers.net.
. 190148 IN NS j.root-servers.net.
. 190148 IN NS a.root-servers.net.
. 190148 IN NS h.root-servers.net.
. 190148 IN NS g.root-servers.net.
. 190148 IN NS l.root-servers.net.
. 190148 IN NS b.root-servers.net.
. 190148 IN NS i.root-servers.net.
. 190148 IN NS d.root-servers.net.
. 190148 IN NS c.root-servers.net.
. 190148 IN NS e.root-servers.net.
. 190148 IN NS m.root-servers.net.
. 190148 IN NS f.root-servers.net.
;; ADDITIONAL SECTION:
a.root-servers.net. 589225 IN A 198.41.0.4
a.root-servers.net. 589225 IN AAAA 2001:503:ba3e::2:30
b.root-servers.net. 335673 IN A 192.228.79.201
b.root-servers.net. 213280 IN AAAA 2001:500:84::b
c.root-servers.net. 463106 IN A 192.33.4.12
c.root-servers.net. 146224 IN AAAA 2001:500:2::c
d.root-servers.net. 463106 IN A 199.7.91.13
d.root-servers.net. 383665 IN AAAA 2001:500:2d::d
e.root-servers.net. 463106 IN A 192.203.230.10
f.root-servers.net. 463106 IN A 192.5.5.241
f.root-servers.net. 81903 IN AAAA 2001:500:2f::f
g.root-servers.net. 463106 IN A 192.112.36.4
h.root-servers.net. 335673 IN A 128.63.2.53
Received 496 bytes from 127.0.1.1#53 in 4 ms
Потом у одного из них спрашиваем NS записи для зоны ru. :
inkvizitor68sl@isera:~$ host -v -t NS ru. 198.41.0.4
Trying "ru"
Using domain server:
Name: 198.41.0.4
Address: 198.41.0.4#53
Aliases:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 40869
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 5, ADDITIONAL: 10
;; QUESTION SECTION:
;ru. IN NS
;; AUTHORITY SECTION:
ru. 172800 IN NS f.dns.ripn.net.
ru. 172800 IN NS e.dns.ripn.net.
ru. 172800 IN NS d.dns.ripn.net.
ru. 172800 IN NS b.dns.ripn.net.
ru. 172800 IN NS a.dns.ripn.net.
;; ADDITIONAL SECTION:
f.dns.ripn.net. 172800 IN A 193.232.156.17
f.dns.ripn.net. 172800 IN AAAA 2001:678:14:0:193:232:156:17
e.dns.ripn.net. 172800 IN A 193.232.142.17
e.dns.ripn.net. 172800 IN AAAA 2001:678:15:0:193:232:142:17
d.dns.ripn.net. 172800 IN A 194.190.124.17
d.dns.ripn.net. 172800 IN AAAA 2001:678:18:0:194:190:124:17
b.dns.ripn.net. 172800 IN A 194.85.252.62
b.dns.ripn.net. 172800 IN AAAA 2001:678:16:0:194:85:252:62
a.dns.ripn.net. 172800 IN A 193.232.128.6
a.dns.ripn.net. 172800 IN AAAA 2001:678:17:0:193:232:128:6
Received 332 bytes from 198.41.0.4#53 in 46 ms
Средний