Nslookup : 8 commandes les plus utilisés

Nslookup est un outils puissant d’administration réseau disponible sur tous les système d’exploitation qui permet d’interroger le serveur DNS afin d’obtenir des informations concernant les nom de domaine, adresses IP et d’autre enregistrement DNS. Dans ce guide nous allons découvrir les meilleurs commande nslookup les plus utilisées.

Si vous ne trouvez pas la commande nslookup  il vous faudra installer le package bind-utils  ( sous centos8 dans mon cas ):

[root@srv ~]# dnf install bind-utils

1- Trouver l’enregistrement A d’un domaine :

[root@srv ~]# nslookup google.com
Server: 192.168.162.2
Address: 192.168.162.2#53

Non-authoritative answer:
Name: google.com
Address: 172.217.16.238
Name: google.com
Address: 2a00:1450:4003:803::200e

2- Vérifier les enregistrements NS d’un domaine:

[root@srv ~]# nslookup -type=ns google.com
Server: 192.168.162.2
Address: 192.168.162.2#53

Non-authoritative answer:
google.com nameserver = ns1.google.com.
google.com nameserver = ns3.google.com.
google.com nameserver = ns4.google.com.
google.com nameserver = ns2.google.com.

Authoritative answers can be found from:

3- Vérifier l’enregistrement SOA d’un domain :

[root@srv ~]# nslookup -type=soa google.com
Server:         192.168.162.2
Address:        192.168.162.2#53

Non-authoritative answer:
google.com
        origin = ns1.google.com
        mail addr = dns-admin.google.com
        serial = 316854466
        refresh = 900
        retry = 900
        expire = 1800
        minimum = 60

Authoritative answers can be found from:

4-Trouver l’enregistrement MX :

[root@srv ~]# nslookup -query=mx google.com
Server: 192.168.162.2
Address: 192.168.162.2#53

Non-authoritative answer:
google.com mail exchanger = 10 aspmx.l.google.com.
google.com mail exchanger = 40 alt3.aspmx.l.google.com.
google.com mail exchanger = 50 alt4.aspmx.l.google.com.
google.com mail exchanger = 20 alt1.aspmx.l.google.com.
google.com mail exchanger = 30 alt2.aspmx.l.google.com.

Authoritative answers can be found from:

5- Comment interroger un serveur DNS spécifique :

[root@srv ~]# nslookup google.com ns1.google.com
Server: ns1.google.com
Address: 216.239.32.10#53

Name: google.com
Address: 172.217.16.238
Name: google.com
Address: 2a00:1450:4003:803::200e

6-Afficher le Revers DNS :

[root@srv ~]# nslookup 172.217.16.238
238.16.217.172.in-addr.arpa name = mad08s04-in-f14.1e100.net.

Authoritative answers can be found from:

7- Changer l’intervalle de timeoute :

[root@srv ~]# nslookup -timeout=20 google.com
Server: 192.168.162.2
Address: 192.168.162.2#53

Non-authoritative answer:
Name: google.com
Address: 172.217.16.238
Name: google.com
Address: 2a00:1450:4003:803::200e

8-Activer le mode debug :

[root@srv ~]# nslookup -debug google.com
Server: 192.168.162.2
Address: 192.168.162.2#53

------------
QUESTIONS:
google.com, type = A, class = IN
ANSWERS:
-> google.com
internet address = 172.217.16.238
ttl = 5
AUTHORITY RECORDS:
ADDITIONAL RECORDS:
------------
Non-authoritative answer:
Name: google.com
Address: 172.217.16.238
------------
QUESTIONS:
google.com, type = AAAA, class = IN
ANSWERS:
-> google.com
has AAAA address 2a00:1450:4003:803::200e
ttl = 5
AUTHORITY RECORDS:
ADDITIONAL RECORDS:
------------
Name: google.com
Address: 2a00:1450:4003:803::200e