Performing DNS lookup on someone's behalf

sanazb · 01-01-2013, 02:57 PM

I'm wondering how can I perform DNS lookup on other's behalf and still receive the result? What should I change in the packet I'm sending?
The reason is that I want to indicate the query is for person x, but return the result to me. so there should be 2 address location in the packet but as I saw dns packet format I did not see that, there is just source address
The reason is that I want to send the request to a CDN and see which replica is returned for somebody else in network?

Thanaks in advance.

routers · 01-02-2013, 01:30 AM

"I'm wondering how can I perform DNS lookup on other's behalf and still receive the result?"

here is the usage
nslookup "domain" "any_public_or_pvt_dns"
# nslookup test.com 8.8.8.8
Server: 8.8.8.8
Address: 8.8.8.8#53

Non-authoritative answer:
Name: test.com
Address: 50.23.225.49

otherwise please post here how u did and what you get

sanazb · 01-02-2013, 12:30 PM

Can you explain the command, I guess test.com is the server you want to get its IP, what is 8.8.8.8?

routers · 01-03-2013, 11:09 PM

8.8.8.8 is the google public dns server, you can use any dns server which is allowed you to do query
example your own local lan dns server

there are several public dns server available in the net
look at this list

http://pcsupport.about.com/od/tipstr...ns-servers.htm

cheers