Very strange internet connectivity issue..have internet but websites unreachable
Okay, I am at the end of my rope with this one. I have had my PC with Windows 7 installed for several months with absolutely no issues until a few days ago. Recently, with no changes other than general software installations and Windows patches, I have started losing connection to the internet after a few hours of uptime. Windows reports that I have internet connection, and I am able to ping internet addresses (google.com, yahoo.com, etc) from a cmd prompt. But I completely lose the ability to reach any website in IE, and cannot connect with Messenger. After rebooting, my connectivity returns for a few hours. I usually notice that it has dropped again after being away from the computer for a while.Here are some of the strange things that I have noticed, and some of the things I have tried while troubleshooting this: - I have a virtual machine installed on this host, and I can reach the internet from the guest O/S of the virtual machine even when the problem is occuring on the host. - I can ping internet addresses, and my router, but I cannot telnet or http to either. I repeat, I cannot even reach my router over http when this is occuring, even though I can ping it and my ipconfig looks normal.- All other PC's on my home network are fine, only my W7 pc is having the problem.- I have tried both my wireless and wired ethernet (on-board), and the pc exhibits the same symptoms regardless of which interface is being used.- I have tried hardcoding an IP address.- I don't see anything out of the ordinary in Event Viewer.The pc acts as if all outgoing ports are blocked for some reason. I'm about one more day of troubleshooting away from re-installing the O/S. I am completely out of ideas on what else to try. If anyone out there has any suggestions, I would be extremely grateful.
March 13th, 2010 8:26am

It sounds as though you could be infected with spyware that may redirect your browser or alter connection settings. Have any changes been made to the host file? In the connection tab of IE options, is a proxy server connection enabled? Doing a quick sweep with HiJackThis or possibly Smitfraud could uncover this if it is the issue.-Scott
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March 13th, 2010 6:39pm

Hi, SaMcp1123's suggestions is worth to try. Meanwhile, I suggest you restart the machine to Safe Mode with Networking and verify whether Internet website can be accessed. If the website cannot be accessed, please upgrade the virus definition and run a complete scan in Safe Mode. If the website can be accessed, please perform a Clean Boot and Reset Internet Explorer 8 settings for a test. Thanks, Novak
March 15th, 2010 9:56am

I will give that hijackthis a try. Should I post the log here or in another forum? As for rebooting, I don't have to reboot in safe mode to get internet back. A normal reboot does the trick. After reboot I will have internet for a few hours before losing it while I am away from the computer. The only way to get it back (that I have found) is to reboot.
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March 15th, 2010 4:55pm

It sounds as though you could be infected with spyware that may redirect your browser or alter connection settings. Have any changes been made to the host file? In the connection tab of IE options, is a proxy server connection enabled? Doing a quick sweep with HiJackThis or possibly Smitfraud could uncover this if it is the issue. -Scott HiJackThis does not support Windows 7 yet. Smitfraud is a actually a type of Spyware. (Check any of the Google results for "smitfraud" for verification.)
March 15th, 2010 6:54pm

Since there is no Internet Connection, I suggest you perform a Clean Boot and Reset Internet Explorer 8 settings to check the result. If the issue persists, please run a virus scanning for a test. Thanks, Novak
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March 16th, 2010 9:46am

Since there is no Internet Connection, I suggest you perform a Clean Boot and Reset Internet Explorer 8 settings to check the result. If the issue persists, please run a virus scanning for a test. Thanks, Novak As I've stated, rebooting always fixes the problem. The problem occurs during periods of inactivity, usually a few hours after reboot. I have found no way to resolve the issue without rebooting. I have checked IE settings, they look fine. Spyhunter scans come back clean. I've also done tests on ports with TELNET before and after the problem starts happening. Host/port combinations that TELNET can connect to before the problem starts, are unreachable after the problem starts. And it is not the destination host that is unreachable, since I can ping them before and after. This leads me to believe that it is not just internet, but rather blocked ports that is the issue. But to my untrained eye, "netstat -a" results look okay to me. I don't know what else to look at.
March 16th, 2010 1:26pm

Hi, I suggest you bypass the router and connect to DSL modem directly via wired cable to check the result. If the issue persists, please collect the following log file for research. Collect the Netmon trace ========================= a. Download NetMon3.3 from the following website and install it on the computer http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=983b941d-06cb-4658-b7f6-3088333d062f b. Launch NetMon3.3. c. In the Microsoft Network Monitor 3.3 window, click Create a new capture tab … d. In the new tab, select all the Network Adapters in the Select Networks window. e. Then, switch to Network Monitor, press F5 to start NetMon. f. Try to join the domain again. When it failed, go to step 7. g. Go back to the NetMon window and press F7 to stop the NetMon. h. Press Ctrl+S to save the Netmon file named test. Then please upload to SkyDrive (www.skydrive.live.com ) and share the link to me. Thanks, Novak
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March 17th, 2010 6:12am

Thanks Novak! That tool helped me figure out the problem myself. I'm still not quite sure of the source of the problem, but I was able to block it anyway. When running NetMon I noticed many hits to my IP from random IP's, but always to the same port (port 14859). My best guess (maybe you can confirm) is that after a few hours something would fill up or get overloaded causing me to be unable send anymore outgoing packets. These hits were happening a lot, like every couple seconds or more. Anyway, I installed ZoneAlarm and cranked it up to max security. It started blocking this incoming traffic and I have not had a drop in connectivity since. The ZoneAlarm explanation was this: "ZoneAlarm Extreme Security blocked traffic to port 14859 on your machine from port 39248 on a remote computer whose IP address is 111.254.209.175. This communication attempt may have been a port scan, or simply one of the millions of unsolicited commercial or network control messages that are routinely sent out over the Internet. Such unsolicited messages are often called Internet background noise." I have tried several antivirus programs and none of them find anything. So I'm not sure how to stop this constant pinging, other than blocking it at my router.
March 19th, 2010 5:25pm

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