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03 Jan 2010  

Windows 7

Problem: New Dell laptop has Windows 7 installed. When connected via wireless, using IE8 I can only browse to sites in the domain. Examples:,, etc. All other sites – for example,, etc. - give me a “page not found error”.

I performed extensive analysis on the problem to isolate the root cause.
1) Reviewed Windows 7 machine.
  • IP address is assigned via DHCP from the comcast wireless router. Router uses WPA, and Windows 7 machine is setup to match router’s ssid and WPA password.
  • From the DOS command prompt, I can successfully ping any domain. This includes,,, etc. Clearly, my Windows 7 machine is on the network, and DNS is working
  • From the DOS command prompt, I can ftp to any ftp site. Again, this proves I am on the network, and that DNS is working.
  • From browser, tried to enter IP address of a site. Tried the IP address for Still could not connect. Again, this further rules out any DNS problems.
  • I installed Mozilla Firefox. Firefox connects to domain but also gives me “page not found errors” for all other domains.
  • I performed a factory reset on IE8 settings. No change.
  • The machine uses the standard Windows 7 firewalls, which I disabled. No change.
  • Removed Dell’s wlan wireless utility and tried to use native Windows 7 wireless utility. No change.
  • Repaired Windows 7 internet connection. No change.
  • Rebooted wireless router. No change.
  • Checked wireless router settings. Pretty standard configuration, nothing fancy. SSID is broadcasting. WPA is used. I changed the WPA password on the router and entered the same password in Windows 7 wireless connection setting. No change.
  • Upgraded BIOS and network card drivers on Windows 7 machine. No change.
2) Tested 2 other machines with Windows XP. XP machines can connect using IE8 and Firefox to all domains successfully. All internet and browser settings in the 2 Windows XP machines are identical to the Windows 7 machine.
3) Turned off security on the wireless router, and modified the wireless settings on the 3 machines. Now the Windows 7 machine and the 2 XP machines can connect to all domains using IE8 successfully.
4) Turned WPA security back on for the wireless router and modified the wireless settings on the 3 machines. Now the problem has returned to the Windows 7 machine, but the 2 XP machines can connect to all domains using IE8 successfully.
5) Connected Windows 7 machine to comcast wireless router via ethernet. The Windows 7 machine can now connect to all domains using IE8 successfully.
6) Took Windows 7 machine to the house of a friend who has AT&T Uverse with a wireless router using WPA. The Windows 7 machine can now connect to all domains using IE8 successfully.

These steps collectively rule out the following potential problems:
- Hardware issues with Dell laptop, including wireless card.
- Drivers.
- Windows 7.
- Network connection settings.
- Specific browsers – both IE8 and Firefox have the problem.
- Browser settings.
- Comcast network.
- Local firewall.
- Dell wireless utility.
- Wireless router settings.
- DNS.
- Other protocols – e.g. ftp works for all domains, but http only works for domain.

This points to a bug in the comcast router firmware. My guess is that the following logic exists in the firmware:
- if operating system is unknown (e.g. the router firmware probably pre-dates Windows 7) AND
- security = WPA AND
- protocol = http,
- then only allow http access to domain and block all other domains.

Most likely, the firmware developer years ago put that in for testing purposes and forgot to remove it, or perhaps the developer did not consider that other operating systems would be released before the firmware was upgraded with the new operating systems.

If I had a Linksys router, for example, I could simply download and install the latest (and hopefully bug-fixed) firmware. Unfortunately, the comcast combination cable modem/wireless router does not give me this capability.

Hence, the best approach for comcast to fix this problem:
1) Replace the current combination cable modem/wireless router with a much more current combination cable modem/wireless router. Test that the Windows 7 machine can connect to all domains using IE8 via wireless (open and WPA) and Ethernet.
2) Install a cable modem only. Make sure the Windows 7 machine via Ethernet can connect to all domains using IE8. Then add a separate wireless router and try to connect over Ethernet plus wireless (open and WPA).

I will let you know what happens once Comcast comes out.
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