This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
OS : Windows 7
Network properties : DHCP and obtain DNS automatically
In office network,
local IP address : 208.*.*.*
DNS (which is chosen automatically based on above mentioned setting) : 208.*.*.* i.e. local/private DNS
Trying to PING one website hosted by third party, can not ping it but I can ping the same website using its IP address and I can open the website in browser without any issues.
i.e. ping www.xyz.com can't resolve to IP address but ping 106.*.*.* (IP of www.xyz.com) works.
and it also works for famous websites like, ping www.google.com works not to mention its IP address ping also works.
So, somehow private/local DNS can't resolve for www.xyz.com but it can for www.google.com why?
And another interesting point is if I change from "obtain DNS automatically" to manual and use google's public DNS 18.104.22.168, above problem disappears. Why? Why my local DNS can resolve for other famous website, but can not resolve for www.xyz.com? What's the practical difference between using public DNS vs private DNS?
A possibility is that your company intentionally blocks some addresses, though I'm not sure whether this is done on the DNS level; I'd expect them to block the IP addresses directly. I'm not an expert, but I believe that the private DNS server might provide names of computers on the intranet; you wouldn't get those if you used a public DNS server.
Just a warning: I tried using Google's DNS server (the 22.214.171.124) in my office some time ago, but it caused some trouble (the other computers didn't see mine), so I had to revert to the office DNS server. And perhaps make sure you're not violating your company policy by using the Google's DNS server.