Only one of three laptops lost internet connection

[Mediaga]

Having lost his internet, a neighbor brought his laptop (Vista SP2, Atheros Wireless) to me last night. His Connection tooltip weirdly stated: Unidentified (Smith wireless).

Network Center showed Unidentified network.

There are 2 other laptops (XP and Windows 7 HP32bit) in his household that have no problems and can connect to the internet just fine. I first checked for viruses, of which I found several, including a rootkit. I cleaned the system up with malwarebytes, but still not connection, so I decided to restore an Acronis system drive image I made for him about a month ago. The results: Same network issues.

His TCP IPV6 & IPV4 properties were what one would expect...Obtain Auto on both counts, however, his IPconfig info for IPV4 were a bit odd. As can be noted from the screenshot, the Autoconfig IPV4 address and subnet mask weren't what I expected to see, nor were the DNS servers. And the Primary DNS suffix was blank.

I was able to correct the problem and get him back on line by manually entering the IPV4 address, Default Gateway, and DNS servers.

But I really wonder what caused this. Again, his was the only machine (out of 3 laptops) that was affected. Why would his (and only his) auto settings suddenly turn on him?

Thanks for any insights.

 

[Fardringle]

One of those viruses may have damaged the DHCP Client Service on the laptop. Or the service may simply have been set to Manual or Disabled. This would explain why the laptop can get online with a static IP address but cannot obtain an address automatically from the DHCP server.

Open the Services applet in the Control Panel and look for DHCP Client Service. Make sure it is set to start automatically. If it is currently started, stop and restart the service.

If that doesn't fix the problem, open a command prompt and type the following command (without the quotes): "netsh winsock reset catalog".

Reboot the computer and have the computer try to get an IP address from the DHCP server again.

 

[Mediaga]

Thanks for your response, Fardringle. I don't have the machine in front of me at the moment. I gave it back to the neighbor, as he needed to get some work done on it, but I can get it back later this evening if necessary.

But, if the winsock issue is/was the problem, wouldn't the restoral of the month old Acronis partition image (a time when there were no issues with his internet connection) have resolved it?

BTW, thanks for the Netsh tip...just learning a lot of this stuff and appreciate the education.

 

[JackMDS]

It might be that his Laptop's software Firewall is Not allowing clean traffic of your Network subnet.

 

[Mediaga]

It might be that his Laptop's software Firewall is Not allowing clean traffic of your Network subnet.

Hi Jack. I hate to 'naysay' every good comment (and all are good suggestions), but it seems likely that restoral of the Acronis image would preclude sofware or configuration issues.

The image was created over a month ago and his issues started occurring just last night. I was sure that restoring the image would correct the issue, but suprisingly, the problem persisted.

This is what confuses me. How could the problem linger?

He does have connectivity after manually entering the IP address, Default Gateway, and DNS servers in the TCP/IPV4 General Properties.

To summarize:

1. He had no internet connectivity
2. The other two laptops in the house work fine
3. Restoring an Acronis image predating his problem by more than a month did not solve the issue.
4. Manual entries into TCP/IPV4 properties restored his internet connectivity.

More:

a. His laptop is Vista SP2 32bit
b. The other 2 laptops are XP and Win7 HP 32
c. He is on a WRT54G router
d. Motorola cable modem

I would almost think that the router was the issue, since it seems that it couldn't be software or configuration (see #3), but if that were the case, why wouldn't the other 2 laptops have issues?

Also, given the image restoral, a Windows Update gone wrong could not be the problem

By process of elimination, it seems like it would have to be a hardware problem with the laptop (i.e., NIC or antenna), but the fact that the manual IPV4 entries solved the problem contradicts that.

So, if I've covered all the bases above, one of my conclusions must either be wrong, or the problem defies explanation.

 

[JackMDS]

You have to find out what is wrong NOW, the obsession with the restore is Not going to solve the problem.


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Assuming that the Router's Wireless is configured correctly that there is a strong signal and the Wireless card on the Computer is physically on.

Go over these steps may be you would find where the breaking point is.
Check the Device Manager for valid Wireless card entry.

http://www.ezlan.net/Win7/net_dm.jpg

If there is No valid entry, delete any Bogus Entry, and re-install the Wireless card's Drivers.

Check the Network connections to make sure that you have a Wireless Network Connection Icon/Entry, and that the Properties of the Icon (right click on the Icon) are correctly configured with TCP/IPv4 protocol in the Network Connections Properties.

http://www.ezlan.net/Win7/net_connection_tcp.jpg

------------------
Many Wireless cards' drivers also install the vendor's Wireless utility.
Make sure that if there is a vendor's Wireless Utility is Not Running together with the Windows native Wireless utility (WLAN Service) .
----------------

Make sure that No Firewall is preventing/blocking the Wireless components to get to the Network.
Some 3rd party Software Firewalls/AV/Security suit,s keep blocking aspects of Local Traffic even it they are turned Off (disabled).
If possible configure the Firewall /Security suit correctly, otherwise totally uninstall it, and get rid of its residual processes to allow clean flow of local network traffic.
If the 3rd party software is uninstalled or disables, make sure that Windows native Firewall is On .
3rd party Network mangers like Bonjour, and NetMagic can block local traffic too.
---------------------------

Working TCP/IP stack should look this way.
Right click on the Wire card Network Connection, choose Status, Details, and see if it got an IP and the rest of the settings.
http://www.ezlan.net/Win7/status-nic.jpg
Description is the card manufacturing data.
Physical address is the card's MAC number.
The xx should be a number from 0 to 255 (all xx same number).
yy should be from 0 to 255
zz should be from 0 to 255 (all zz the same number.
The lease date should be valid to the current time.

*Note 1. IP that starts with 169.xxx.xxx.xxx is not valid functional IP.

*Note 2. There might be an IPv6 entries too. However, they are not functional for Internet traffic or LAN. They are needed for Win 7 special HomeGroup configuration. ---------------------------------------------------

A message in the Wireless little Window that says Connected does not means that your are really have a valid functional connection.
If everything above is OK you have to be able to connect to the Router.
Connecting to the Router means that you can enter the Router's core IP into an address bar of a browse, be able to connect, see, and configure the Router's menus.

If it does not connecting to the Router, log from any computer that can connect to Wireless Router with a Wire, disable the Wireless Security, make sure that the Wireless broadcast SSID is On, and try to connect with No Wireless security.

Enable the Wireless security after you mange to establish a functional connection.

 

[Mediaga]

...Assuming that the Router's Wireless is configured...

Thanks for the nice writeup. I've actually copy and pasted this for future troubleshooting reference.

It may be a little while before I regain access to the laptop in question, as the manual entires give him internet access, which is what he wanted.

You have to find out what is wrong NOW, the obsession with the restore is Not going to solve the problem.

uh, "obsession"? A restore to an image a month earlier that wasn't exhibiting the problem doesn't correct the problem and you seem to consider that irrelevant? Deductive logic dictates that it be considered a potentially significant factor, not discounted.

Further, while you may be qualified to give network advice, that hardly qualifies you to make such speculative statements. I suggest you stick to technical advice and tone down the arrogance a bit.

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