Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I'm trying to remotely assist a friend with a problem the likes of which I've never seen before.

He has a new HP Win7 laptop works perfectly when using a WIRED connection to his home network (Comcast supplied cable router). Other machines, including old WinXP laptop, MacBook, and new Dell Win7 Laptop, also work perfectly when using either a WIRED or a WIRELESS connection.

However, the new HP Win7 machine will only "sorta" work when using a WIRELESS connection. The "sorta" is the part that is truly bizarre to me. This sounds crazy, but it apparently can access sites in the local geographic region. My friend is in the Atlanta suburbs and can, for example, access sites from local universities like,, as well as a site from a local company known to have its servers hosted in downtown Atlanta. However, my friend CANNOT access large national sites such as,,, etc. When I say "cannot access", I mean that he gets "Web site found, waiting for reply" in the status bar for a long time, then eventually an error about site cannot be accessed.

To add to the mystery, he CAN access with no problem, can even get search results no problem.

I've done lots of research and I've had him try various suggestions but none have worked. Pretty much any explanation I have found seems to make no sense regarding the "can access some sites but not others" problem. For example, a commonly cited issue is MAC address filtering. That would make sense if he couldn't get to ANY sites, but doesn't explain why he can get to some but not others.

I am at my wit's end! Any suggestions? Unfortunately, troubleshooting is greatly complicated by the fact that my friend is not computer savvy, and I don't have physical access to the machine or network in question. I have to do everything remotely by telephone instruction, which is tedious to say the least.

share|improve this question
Someone came to me with the same problem. A new Dell could not connect with wifi to a Comcast router. And I could only access google sites, but I could ping yahoo. The common factor is Comcast and Win7 wireless. Not sure what is different with win7 and wireless. – nportelli Jan 26 '10 at 15:47

Few things off the top of my head...

  1. Open a command prompt as an Admin and run "ipconfig /flushdns".
  2. Open Network Connections, right click on the Wireless connection and select Repair.
  3. Change the DNS servers on his wireless connection to and (Google DNS). You could also change the DNS settings on his router and if you don't want Google DNS then use OpenDNS (but you need to sign up for an account).
  4. Download and run the software WinSockFix.
share|improve this answer

It almost sounds like you have an incorrect MTU setting on your wireless adapter. MTU set too high can cause this exact problem - being able to access some websites but not others.

Manually determine your best MTU setting and then set it from the command prompt. Although Windows 7 usually does a top job of automatically adjusting this on-the-fly, sometimes it does get it wrong. The MTU setting can be different for each network adapter, so you can leave your wired network adapter as it is.

share|improve this answer
Can you expand your answer with what MTU is and where someone would look for a setting? – fixer1234 Nov 2 '14 at 2:35

I wanted to chime in here for steps that corrected my issue albeit five years later. Very similar setup, Win7 laptop on Comcast Xfinity. Wireless connection would ONLY get google, wikipedia, facebook, as a small handful of sites. All others were timed out. I had to resort to calling Comcast.

Steps that corrected my issue: Removing the Wireless NIC from Windows.

  1. Start -> Run -> devmgmt.msc
  2. Right click your adapter and select "uninstall".
  3. Click OK (do NOT enable the checkbox for removing drivers)
  4. Reboot
  5. Connect to the wireless router ssid

Success (I could now get to where I couldn't before)

share|improve this answer

First the remote access. If he is ok with letting you access his machine, and the machine can go there, he could sign up for a free account and give you the password. When done, he can disable the software and/or change the password.

Here are some assumptions I'm making, the wireless connection is WiFi and not a cellular carrier, because that could be a whole different set of problems.

As far as the WiFi connection in Windows, I would ensure the IP address and DNS is provided by the router (assuming that is how he has that configured for the wired settings). I would compare the IPCONFIG /ALL of the wired and WiFi connections.

If the WiFi connections look good, I would ping the access point because the WiFi signal could be poor quality, (all though I'm not sure why some pages will load unless only the small pages will load without error and larger complicated pages error out because of the poor WiFi signal quality.)

If you can ping the router ok and the DNS settings are the same as the wired connection, then perhaps some kind of security software is messing with the connection. I've had odd results transitioning a laptop from wired to WiFi. It turned out Norton would block what it though was the unused connection, so when I transitioned it too a little while for it to catchup. You may want to disable this kind of software for the test.

This does sound like a winner of a problem, I wish you both luck.

(By the way, OpenDNS doesn't require an account to use, only if you want to use advanced features like filtering then you need an account so it know what setting to apply to your IP address.)

share|improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .