dns queries

Platform: - Linux and windows
Keywords: - DNS queries using nslookup
Author: - Dinesh Aggarwal

Most of us are aware about the normal functionalities of nslookup command.

It is used to resolve domain name into ip address and ip address into domain names.

C:\>nslookup
Default Server:  ns3.ncr.airtelbroadband.in
Address:  202.56.215.55

> google.com
Server:  ns3.ncr.airtelbroadband.in
Address:  202.56.215.55

Non-authoritative answer:
Name:    google.com
Addresses:  64.233.187.99, 64.233.167.99, 72.14.207.99

> yahoo.com
Server:  ns3.ncr.airtelbroadband.in
Address:  202.56.215.55

Non-authoritative answer:
Name:    yahoo.com
Addresses:  216.109.112.135, 66.94.234.13
> 66.94.234.13
Server:  ns3.ncr.airtelbroadband.in
Address:  202.56.215.55

Name:    w2.rc.vip.scd.yahoo.com
Address:  66.94.234.13

Here 202.56.215.55 is the ip address of ISP. By typing yahoo.com we get to know the ip addresses of domain name yahoo.com and by typing 66.94.234.13 we got to know the domain name associated with this IP address.

There are much more uses of command nslookup.

To see all the DNS servers of a domain name:-

C:\>nslookup
Default Server:  ns3.ncr.airtelbroadband.in
Address:  202.56.215.55

> set type=ns
> yahoo.com
Server:  ns3.ncr.airtelbroadband.in
Address:  202.56.215.55

Non-authoritative answer:
yahoo.com       nameserver = ns8.yahoo.com
yahoo.com       nameserver = ns5.yahoo.com
yahoo.com       nameserver = ns6.yahoo.com
yahoo.com       nameserver = ns4.yahoo.com
yahoo.com       nameserver = ns2.yahoo.com
yahoo.com       nameserver = ns1.yahoo.com
yahoo.com       nameserver = ns3.yahoo.com

ns2.yahoo.com   internet address = 68.142.255.16
ns1.yahoo.com   internet address = 66.218.71.63
ns3.yahoo.com   internet address = 217.12.4.104
ns4.yahoo.com   internet address = 68.142.196.63
ns5.yahoo.com   internet address = 216.109.116.17
ns6.yahoo.com   internet address = 202.43.223.170
ns8.yahoo.com   internet address = 202.165.104.22

(Above are the DNS servers of yahoo.com)

 

> google.com
Server:  ns3.ncr.airtelbroadband.in
Address:  202.56.215.55

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

ns1.google.com  internet address = 216.239.32.10
ns2.google.com  internet address = 216.239.34.10
ns3.google.com  internet address = 216.239.36.10
ns4.google.com  internet address = 216.239.38.10

 

(Above are the DNS servers of google.com)

To see all the mail servers of a domain name:-

C:\>nslookup
Default Server:  ns3.ncr.airtelbroadband.in
Address:  202.56.215.55

> set type=mx
> yahoo.com
Server:  ns3.ncr.airtelbroadband.in
Address:  202.56.215.55

Non-authoritative answer:
yahoo.com       MX preference = 1, mail exchanger = d.mx.mail.yahoo.com
yahoo.com       MX preference = 1, mail exchanger = e.mx.mail.yahoo.com
yahoo.com       MX preference = 1, mail exchanger = f.mx.mail.yahoo.com
yahoo.com       MX preference = 1, mail exchanger = g.mx.mail.yahoo.com
yahoo.com       MX preference = 1, mail exchanger = a.mx.mail.yahoo.com
yahoo.com       MX preference = 1, mail exchanger = b.mx.mail.yahoo.com
yahoo.com       MX preference = 1, mail exchanger = c.mx.mail.yahoo.com

yahoo.com       nameserver = ns5.yahoo.com
yahoo.com       nameserver = ns4.yahoo.com
yahoo.com       nameserver = ns2.yahoo.com
yahoo.com       nameserver = ns3.yahoo.com
yahoo.com       nameserver = ns1.yahoo.com
yahoo.com       nameserver = ns8.yahoo.com
yahoo.com       nameserver = ns6.yahoo.com
c.mx.mail.yahoo.com     internet address = 68.142.237.182
c.mx.mail.yahoo.com     internet address = 216.39.53.3
d.mx.mail.yahoo.com     internet address = 216.39.53.2
e.mx.mail.yahoo.com     internet address = 216.39.53.1
f.mx.mail.yahoo.com     internet address = 68.142.202.247
f.mx.mail.yahoo.com     internet address = 209.191.88.247
g.mx.mail.yahoo.com     internet address = 206.190.53.191
g.mx.mail.yahoo.com     internet address = 209.191.88.239
a.mx.mail.yahoo.com     internet address = 209.191.118.103
b.mx.mail.yahoo.com     internet address = 66.196.97.250
ns2.yahoo.com   internet address = 68.142.255.16
ns1.yahoo.com   internet address = 66.218.71.63
ns3.yahoo.com   internet address = 217.12.4.104
ns4.yahoo.com   internet address = 68.142.196.63

(The mail servers of yahoo.com are 
c.mx.mail.yahoo.com,
c.mx.mail.yahoo.com
d.mx.mail.yahoo.com   
e.mx.mail.yahoo.com    
f.mx.mail.yahoo.com    
f.mx.mail.yahoo.com    
g.mx.mail.yahoo.com    
g.mx.mail.yahoo.com    
a.mx.mail.yahoo.com  
b.mx.mail.yahoo.com   )

> google.com
Server:  ns3.ncr.airtelbroadband.in
Address:  202.56.215.55

Non-authoritative answer:
google.com      MX preference = 10, mail exchanger = smtp1.google.com
google.com      MX preference = 10, mail exchanger = smtp2.google.com
google.com      MX preference = 10, mail exchanger = smtp3.google.com
google.com      MX preference = 10, mail exchanger = smtp4.google.com

google.com      nameserver = ns2.google.com
google.com      nameserver = ns4.google.com
google.com      nameserver = ns1.google.com
google.com      nameserver = ns3.google.com
smtp1.google.com        internet address = 72.14.203.25
smtp2.google.com        internet address = 64.233.167.25
smtp3.google.com        internet address = 64.233.183.25
smtp4.google.com        internet address = 72.14.215.25
ns1.google.com  internet address = 216.239.32.10
ns2.google.com  internet address = 216.239.34.10
ns3.google.com  internet address = 216.239.36.10
ns4.google.com  internet address = 216.239.38.10

To see SOA, refresh time, TTL etc of a domain name:-

> set type=SOA
> yahoo.com
Server:  ns3.ncr.airtelbroadband.in
Address:  202.56.215.55

Non-authoritative answer:
yahoo.com
        primary name server = ns1.yahoo.com
        responsible mail addr = hostmaster.yahoo-inc.com
        serial  = 2007100201
        refresh = 3600 (1 hour)
        retry   = 300 (5 mins)
        expire  = 1814400 (21 days)
        default TTL = 600 (10 mins)

yahoo.com       nameserver = ns5.yahoo.com
yahoo.com       nameserver = ns3.yahoo.com
yahoo.com       nameserver = ns8.yahoo.com
yahoo.com       nameserver = ns2.yahoo.com
yahoo.com       nameserver = ns1.yahoo.com
yahoo.com       nameserver = ns4.yahoo.com
yahoo.com       nameserver = ns6.yahoo.com
ns2.yahoo.com   internet address = 68.142.255.16
ns1.yahoo.com   internet address = 66.218.71.63
ns3.yahoo.com   internet address = 217.12.4.104
ns4.yahoo.com   internet address = 68.142.196.63
ns5.yahoo.com   internet address = 216.109.116.17
ns6.yahoo.com   internet address = 202.43.223.170
ns8.yahoo.com   internet address = 202.165.104.22

 

> google.com
Server:  ns3.ncr.airtelbroadband.in
Address:  202.56.215.55

Non-authoritative answer:
google.com
  primary name server = ns1.google.com
        responsible mail addr = dns-admin.google.com
        serial  = 2007092700
        refresh = 7200 (2 hours)
        retry   = 1800 (30 mins)
        expire  = 1209600 (14 days)
        default TTL = 300 (5 mins)

google.com      nameserver = ns4.google.com
google.com      nameserver = ns3.google.com
google.com      nameserver = ns1.google.com
google.com      nameserver = ns2.google.com
ns1.google.com  internet address = 216.239.32.10
ns2.google.com  internet address = 216.239.34.10
ns3.google.com  internet address = 216.239.36.10
ns4.google.com  internet address = 216.239.38.10

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