If your ISP is Comcast, then probably your Internet connection is not stable. you would think a giant ISP like Comcast would have redundancy on their DNS Servers, or another sort of reliability strategy, but nay, their DNS servers keep going down, and fixing the problem does not seems to be their priority.

for those non-tech people let me explain what DNS does and why is so important. DNS stands for Domain Name System and it’s the mechanism that translates website names to IP addresses.for example, when you type forevergeeks.com on your web browser address bar, the browser sends a request to a DNS server to translate that name “forevergeeks” to an IP address. computers do not understand names ( that was invented because it is easier for us to remember ) you can get to Google either using http://google.com or by typing the IP address http://173.194.33.104/ the difference is that the first option requires a DNS server to translate the name, the latter does not. but like I said, we use names because they are easier to remember.

Now, if there is no DNS servers available to translate website names to IP addresses, your browser will display an error saying that the web page was not found. and this is what I been getting a lot lately. I knew almost immediately the problem was DNS, but I started blaming my cheap Netgear wireless router for the problem, but it puzzled me why I could get to websites using the IP address but not the name. I was getting suspicious, so I did a short search on Google regarding the issue, and found the problem to be common among Comcast users. but still I was not convinced why Comcast would have that issue, then a few days later it was all over the news that Comcast Internet service was disrupted because of DNS issues.. oh boy said I, these people finally found out what I been having for awhile.

But to be honest, I been using Comcast services for about 10 years and never have had mayor issues with them, and this DNS problem can be solved easily without getting downgraded 10 years behind by using a Verizon DSL connection, because that’s  the only alternate service currently available in my area. my solution is to use other DNS servers rather than the ones provided by Comcast automatically. there are many free DNS services, the most famous are opendns.org and Google. I would choose the latter when it comes to trust.

Google DNS server IP addresses are 8.8.8.8 and 8.8.4.4 and you can enter them on your computer or your router. I  recommend using these DNS IP addresses at the router level, in that way you don’t change any settings on the computer.

In the following tutorial I will show you how I changed the DNS IP addresses on the Netgear router I have, but most home routers follow the same  procedure so this should give you an idea on how to do it on your router as well.

open your browser, and type the IP address of your router. mine is 192.168.1.1 ( default ) if you don’t know the IP address of your router, open the command prompt, and type “ipconfig” normally the “gateway” IP address is the IP address of your router.

the login window should come up.

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type the username and password. if you haven’t entered any username and password for the router, check the documentation for the default username and password.

Once inside the router web page, click on “Basic Settings” and under the Domain Name Server (DNS) Address option, select Choose These DNS Servers and type the Google numbers as listed above. one as primary and the other as secondary.

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Once you have entered the Google DNS numbers, click on Apply. that will disconnect your Internet connection ( if you are connected to the router ) to update the new DNS servers.

that should fix your Comcast DNS problem.

13 thoughts on “What’s up with Comcast DNS problem?

  1. Do you know how to correct problems with blocking certain sites? Just keeps saying this site is being blocked. And it has nothing to do with parental controls and the sites aren't pornographic in nature or anything.

    Reply
  2. Thanks for posting. Even after the Comcast outage on 12/5 I continue to have issues with their DNS servers. I'm switching to googles for good at this point.

    Reply
  3. Thanks for the tip. New Comcast user here from Marin and I have been having odd problems – image files and CSS files from some sites are not loading, and some sites that simply fail to open (well-known sites that I know are online). It is sporadic and annoying. We didn’t have this problem with AT&T. I just updated the DNS server settings on our wifi router and I am crossing my fingers. Thanks again!

    Reply
    • most likely that is an ongoing problem with Comcast DNS servers. change your DNS IP addresses to Google or OPENDNS and see if you continue having the issue. these type of problems can be caused by a faulty router as well.

      cheers,

      Reply
  4. Thank you!
    Apple released the new iOS 5.1 update and for days I wasn’t been able to update none of my devices (iPad 1, iPhone 4 and Apple TV2). I was getting a bit irritated so I decided to do some research. I read that this was a common problem and the one easy solution was to change the DNS on your devices to Google’s 8.8.8.8.
    This trick worked perfectly for all devices however I remained intrigued as no one really explained how that worked.
    I now finally understand it thanks to your post :)

    Reply
  5. Thanks for the article. I’ve been monkeying with my network, changing between gateway/routers, and run into this issue. For example, I’m putting a Linksys wired gateway/router on my internet connection and even though the status tab shows it connected to the Comcast DNS, I get no DNS service. I can ping IPs on the net, including my public IP, with no problem. Also, using DHCP, so the connection from my NIC should happen automatically.
    I’ll give Google DNS a try.

    Reply
  6. It’s great how the “experts” on comcast’s forums try to tell you to attempt x,y,z,f and that, to fix your slow “network”, and how using outside dns is bad, yet when you set up google dns, suddenly loading websites is blazing fast and all the “network” problems you had disappear, despite not changing anything regarding your networking outside of where you get your DNS services.

    /sigh
    It’s a shame that so many people have problems on what is otherwise an outstanding network, simply due to shoddy dns services. What a waste… so easy to fix too.

    Reply

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