DNS upiti pomocu dig alata.

Koristiti cemo dig alat za upit dns domenskih postavki.

Instalacija.
apt-get install dnsutils
Procedura za dobijanje liste Name Servera za domenu:
  • dobijanje liste svih root servera
  • upit na bilo koji root server za AUTHORITATIVE GTLD(Generic Top Level Domain) dns servere
  • upit na GTLD server

1. Dobijanje liste svih root servera

Dig bez argumenata dat ce listu root servera

$ dig +short
j.root-servers.net.
g.root-servers.net.
l.root-servers.net.
c.root-servers.net.
e.root-servers.net.
f.root-servers.net.
h.root-servers.net.
i.root-servers.net.
m.root-servers.net.
d.root-servers.net.
a.root-servers.net.
b.root-servers.net.
k.root-servers.net.

2. Upit na bilo koji root server za AUTHORITATIVE GTLD(Generic Top Level Domain) dns servere

Uzmite bilo koji root server i postavite upit za GTLD server
$ dig @c.root-servers.net debian.org

; <<>> DiG 9.10.3-P4-Ubuntu <<>> @c.root-servers.net debian.org
; (2 servers found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 15573
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 6, ADDITIONAL: 13
;; WARNING: recursion requested but not available

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;debian.org.			IN	A

;; AUTHORITY SECTION:
org.			172800	IN	NS	a2.org.afilias-nst.info.
org.			172800	IN	NS	a0.org.afilias-nst.info.
org.			172800	IN	NS	d0.org.afilias-nst.org.
org.			172800	IN	NS	b0.org.afilias-nst.org.
org.			172800	IN	NS	b2.org.afilias-nst.org.
org.			172800	IN	NS	c0.org.afilias-nst.info.

;; ADDITIONAL SECTION:
a0.org.afilias-nst.info. 172800	IN	A	199.19.56.1
a2.org.afilias-nst.info. 172800	IN	A	199.249.112.1
b0.org.afilias-nst.org.	172800	IN	A	199.19.54.1
b2.org.afilias-nst.org.	172800	IN	A	199.249.120.1
c0.org.afilias-nst.info. 172800	IN	A	199.19.53.1
d0.org.afilias-nst.org.	172800	IN	A	199.19.57.1
a0.org.afilias-nst.info. 172800	IN	AAAA	2001:500:e::1
a2.org.afilias-nst.info. 172800	IN	AAAA	2001:500:40::1
b0.org.afilias-nst.org.	172800	IN	AAAA	2001:500:c::1
b2.org.afilias-nst.org.	172800	IN	AAAA	2001:500:48::1
c0.org.afilias-nst.info. 172800	IN	AAAA	2001:500:b::1
d0.org.afilias-nst.org.	172800	IN	AAAA	2001:500:f::1

;; Query time: 53 msec
;; SERVER: 192.33.4.12#53(192.33.4.12)
;; WHEN: Tue Jan 31 18:06:04 CET 2017
;; MSG SIZE  rcvd: 441

3. Upit na GTLD server

$ dig @b0.org.afilias-nst.org debian.org

; <<>> DiG 9.10.3-P4-Ubuntu <<>> @b0.org.afilias-nst.org debian.org
; (2 servers found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 16453
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 3, ADDITIONAL: 3
;; WARNING: recursion requested but not available

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;debian.org.			IN	A

;; AUTHORITY SECTION:
debian.org.		86400	IN	NS	dnsnode.debian.org.
debian.org.		86400	IN	NS	sec2.rcode0.net.
debian.org.		86400	IN	NS	sec1.rcode0.net.

;; ADDITIONAL SECTION:
dnsnode.debian.org.	86400	IN	A	194.146.106.126
dnsnode.debian.org.	86400	IN	AAAA	2001:67c:1010:32::53

;; Query time: 52 msec
;; SERVER: 199.19.54.1#53(199.19.54.1)
;; WHEN: Tue Jan 31 18:06:36 CET 2017
;; MSG SIZE  rcvd: 153
Dig ce dati odgovor sa AUTHORITY SECTION gdje se moze naci AUTHORITY name server
Generic dig upit
Dobijanje bilo kojih postavki
$ dig +short any debian.org
sec1.rcode0.net.
dnsnode.debian.org.
sec2.rcode0.net.
Dobijanje MX recorda za debian.org
$ dig +short mx debian.org
0 mailly.debian.org.
0 muffat.debian.org.

OBJASNJENJE

Koristenje komande dig bez +short opcije
Kada se korisit +short opcija dobija se samo dio iz ANSWER SECTION

QUESTION SECTION

Mozemo vidjeti koji smo upit postavili.

ANSWER SECTION

Unutar odjeljka mozemo vidjeti odgovor za trazeni upit.

Dobijanje NS servera za debian.org
$ dig +short ns debian.org
dnsnode.debian.org.
sec1.rcode0.net.
sec2.rcode0.net.
Dobijanje A recorda za www.debian.org
$ dig +short a debian.org
5.153.231.4
140.211.15.34
128.31.0.62
130.89.148.14