Nslookup : 8 most used commands :

Nslookup is a powerful network administration tool available on all operating systems that allows you to query the DNS server to obtain information about domain names, IP addresses and other DNS records.

In this tutorial we will discover the most used nslookup commands.

If you cannot find the nslookup command, you will need to install the bind-utils package, below an example on CentOS 8 :

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

1- Find the A record of a domain :

[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- Check a domain’s NS records:

[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- Check the SOA record of a 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- Find the MX record:

[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- How to query a specific DNS server:

[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- Display DNS Reverse :

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

7- Change the timeout interval:

[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- Enable debug mode:

[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

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