Is your DNS down?

April 14, 2011

Ever been happily browsing the web, but found that you weren’t able to load web pages anymore?

Well, it’s either your computer, or your network. If it’s your network, you might want to see if your ISP’s DNS servers are offline. Go to an IP address of a known site (such as 69.63.181.11 for Facebook, 74.125.224.72 for Google) and see if you can browse those sites normally. If you can’t, then your problem isn’t DNS related and some other tutorial on the Internet may help.

First, the question some may be asking is “What is DNS, and why should I care?” Simply put, DNS is the phonebook for the Internet. You put in the URL “google.com” and a DNS server returns “74.125.224.72,” so that your computer can find the server that you requested. It’s easy to remember a domain name, but not so easy for a person to remember a huge amount of IP addresses. This system makes it easier to browse the web.

Now, if you have found your problem to be DNS related, here is what you should do: use a free DNS provider. Two good services happen to be OpenDNS and Google Public DNS. Google Public DNS is free, but OpenDNS has free and paid versions. I find that the free version of OpenDNS works well for my personal use. They even have a page for someone to visit when they know that their current DNS servers are not functioning (208.69.38.205) and they will offer assistance if you tweet them @OpenDNS.

If a friend asks what to do about their “broken Internet,” you can just tell them what you were told here and possibly save the day.

4 comments

  1. Jake - April 14, 2011 1:24 am

    Or, before you go changing your dns servers, you can try the following on windows machines:

    Start->Run
    cmd
    ipconfig \flushdns
    exit

    That should flush the dns cache, allowing new queries to be built on the fly. If it still doesn’t work, you might have a malware proxy running. Then try the command “netsh winhttp reset proxy”. If neither of those work, THEN try changing your dns settings.

    Reply
    • Chris Ellison - April 14, 2011 1:55 am

      Very good point. I was only trying to inform people that the DNS servers of any ISP can fail, with no failover protection to ensure DNS connectivity. OpenDNS and Google Public DNS has the redundancy required by major corporations, so I would trust them not to fail as often or as hard.

      Reply

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