Pirmiausiai susisiekiama su šakniniu DNS serveriu, kuris turi sąrašą visų .lt vardų, pilnas komponentas dar vadinamas (TLD)(top-level domain) . Užklausos tesiasi, kol gaunamas vis tikslesnis atsakymas.
2013 varasio menesį buvo apibūdinta 13 root serverių, prasidedančių - raide.root-servers.net
Šiuo metu pasaulyje yra 7 autoritetiniai .LT srities vardų serveriai: Pirminis: a.tld.lt
Patikrinimas:
Naudojamos komandos: nslookup
Ieškomas domenas: http://akl.lt
C:\Windows\system32>nslookup
> server a.root-servers.net
Default Server: a.root-servers.net
Addresses: 2001:503:ba3e::2:30
198.41.0.4
> server 198.41.0.4
Default Server: [198.41.0.4]
Address: 198.41.0.4
> akl.lt
Server: [198.41.0.4]
Address: 198.41.0.4
Name: akl.lt
Served by:
- a.tld.lt
195.8.218.131
lt
- b.tld.lt
194.0.20.1
2001:678:19::1
lt
- c.tld.lt
194.0.1.4
2001:678:4::4
lt
- d.tld.lt
194.0.3.1
2001:678:6::1
lt
- e.tld.lt
194.0.18.1
lt
- f.tld.lt
194.0.19.1
2001:678:8c::1
lt
> server 195.8.218.131
in-addr.arpa nameserver = a.in-addr-servers.arpa
in-addr.arpa nameserver = b.in-addr-servers.arpa
in-addr.arpa nameserver = c.in-addr-servers.arpa
in-addr.arpa nameserver = d.in-addr-servers.arpa
in-addr.arpa nameserver = e.in-addr-servers.arpa
in-addr.arpa nameserver = f.in-addr-servers.arpa
a.in-addr-servers.arpa internet address = 199.212.0.73
b.in-addr-servers.arpa internet address = 199.253.183.183
c.in-addr-servers.arpa internet address = 196.216.169.10
d.in-addr-servers.arpa internet address = 200.10.60.53
e.in-addr-servers.arpa internet address = 203.119.86.101
f.in-addr-servers.arpa internet address = 193.0.9.1
a.in-addr-servers.arpa AAAA IPv6 address = 2001:500:13::73
b.in-addr-servers.arpa AAAA IPv6 address = 2001:500:87::87
c.in-addr-servers.arpa AAAA IPv6 address = 2001:43f8:110::10
d.in-addr-servers.arpa AAAA IPv6 address = 2001:13c7:7010::53
e.in-addr-servers.arpa AAAA IPv6 address = 2001:dd8:6::101
f.in-addr-servers.arpa AAAA IPv6 address = 2001:67c:e0::1
Default Server: [195.8.218.131]
Address: 195.8.218.131
> server 195.8.218.131
Default Server: [195.8.218.131]
Address: 195.8.218.131
Name: akl.lt
Served by:
- ns3.serveriai.lt
109.235.65.142
akl.lt
- ns1.serveriai.lt
79.98.25.142
akl.lt
- ns4.serveriai.lt
192.96.207.142
akl.lt
- ns2.serveriai.lt
79.98.29.142
akl.lt
> server 109.235.65.142
Default Server: [109.235.65.142]
Address: 109.235.65.142
> akl.lt
Server: [109.235.65.142]
Address: 109.235.65.142
Name: akl.lt
Address: 193.219.42.13
--kitos komandos pasirinkus serverį--
# ieškant tik ns įrašų:
--set type=ns
# įgalinant zonos transfer, parodo zonos turinį
ls -d name.lt
Užklausa baigta, rastas domeno ip adresas. Apačioje, nuotraukoje matome DNS užklausą, su wireshark programa.
Gnu/Linux dns lookup
$ dig www.akl.lt
arba
$ host -a akl.lt
; <<>> DiG 9.9.5-3-Ubuntu <<>> www.akl.lt
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 53507
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 4, ADDITIONAL: 5
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;www.akl.lt. IN A
;; ANSWER SECTION:
www.akl.lt. 1800 IN A 193.219.42.13
;; AUTHORITY SECTION:
akl.lt. 3600 IN NS ns2.serveriai.lt.
akl.lt. 3600 IN NS ns3.serveriai.lt.
akl.lt. 3600 IN NS ns1.serveriai.lt.
akl.lt. 3600 IN NS ns4.serveriai.lt.
;; ADDITIONAL SECTION:
ns1.serveriai.lt. 1275 IN A 79.98.25.142
ns2.serveriai.lt. 908 IN A 79.98.29.142
ns3.serveriai.lt. 72 IN A 109.235.65.142
ns4.serveriai.lt. 2821 IN A 192.96.207.142
;; Query time: 13 msec
;; SERVER: 127.0.1.1#53(127.0.1.1)
;; WHEN: Wed Jul 16 03:38:12 EEST 2014
;; MSG SIZE rcvd: 201
# Komanda ieškanti MX įrašų:
$ dig akl.lt MX
# Komanda pakeikianti 'who is' informacija apie domeną
$ whois akl.lt
Šakninių komenų paieška:
$ dig NS lt. @k.root-servers.net
;; AUTHORITY SECTION:
lt. 172800 IN NS a.tld.lt.
lt. 172800 IN NS b.tld.lt.
lt. 172800 IN NS c.tld.lt.
lt. 172800 IN NS d.tld.lt.
lt. 172800 IN NS e.tld.lt.
lt. 172800 IN NS f.tld.lt.
Literatūra:
https://en.wikipedia.org/wiki/Root_name_server
https://lt.wikipedia.org/wiki/DNS
https://www.youtube.com/watch?v=zl6bf2auvAE
http://www.dnsknowledge.com/whatis/tld-name-server/
