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What is non-authoritive answer in nslookup?

Does it mean the answer I got is not from the reliable source? how to get the 'authoritative' answer?

bash-3.2$ nslookup google.com
Server:		4.2.2.1
Address:	4.2.2.1#53
 
Non-authoritative answer:
Name:	google.com
Address: 74.125.67.100
Name:	google.com
Address: 209.85.171.100
Name:	google.com
Address: 74.125.45.100

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fdduran

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SOLUTION

arnold

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beer9

ASKER

I see this configuration in /etc/resolv.conf where 192.168.0.1 is my netgear wifi router. so 192.168.0.1 is serving as both the default gateway and default DNS server. I am not sure whether there is any DNS server is running on 192.168.0.1. But still it is helping to resolve the DNS name. I can not telnet to 192.168.0.1 on port 53

I have configured 4.2.2.1 and 4.2.2.2 as the primary and secondary DNS server in my wifi router(192.168.0.1). How this name query transaction is happening?

bash-3.2$ cat /etc/resolv.conf 
nameserver 192.168.0.1
 
---
 
bash-3.2$ telnet 192.168.0.1 53
Trying 192.168.0.1...
^C
bash-3.2$
 
---
 
bash-3.2$ nslookup google.com 
Server:		192.168.0.1
Address:	192.168.0.1#53
 
Non-authoritative answer:
Name:	google.com
Address: 74.125.67.100
Name:	google.com
Address: 209.85.171.100
Name:	google.com
Address: 74.125.45.100

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omarfarid

please see:

http://en.wikipedia.org/wiki/Domain_Name_System#Address_resolution_mechanism

arnold

In short DNS works on both UDP and TCP port 53. The TCP connection mode is used for large data transfers. Normally routers that provide dns responses only listen on UDP 53 port only.

beer9

ASKER

Thank you :-)