localized network connectivity problems

Posted on 2012-09-08
Last Modified: 2013-01-23
I have come across 3 computers this week that all seem to have the same problem.  The customers says they are not able to connect to their wifi and/or have no internet access.

  On location I have verified the problem.  Despite resetting routers, resetting the connection, manually setting IP address etc, I am not able to fix the problem.   I can connect my laptop w/o a problem - so it seems machine specific and not network related.  If I use ethernet to connect rather than wireless I have the same problem.
Other computers on the same network work fine.

The machines appear clear of viruses, as I have also scanned and cleaned them.  They all are able to get DNS resolution.  

Here is the odd part.  When I take them to another location - my home or my office, they connect fine.  When I return them they won't connect.  

Has anyone heard of a problem like this?
Question by:jbasiliere67
    LVL 19

    Expert Comment

    did you check the network infrastructure for loopback? If there is not somewhere there both sides of one UTP cable connected to the same switch/router/floor box/other network device?
    LVL 82

    Accepted Solution

    Do they all have expired copies of Norton or some other Anti-virus?  Anti-virus programs scan your internet traffic by setting up a proxy on your computer.  Norton in particular is infamous for blocking traffic thru that proxy when it expires or isn't removed properly.
    LVL 38

    Expert Comment

    I don't know how complex your network is, but some networks participate in 802.1x authentication for access to the wired and wireless networks. Without authorization, you are not talking.

    This is usually on a highly complex WAN for ITSec purposes. Many businesses use 802.1x with a RADIUS or TACACs server for RF (radio frequency) links like Wireless networks to secure them.

    Author Comment

    No, this is a simple network.  It has a ISP cable modem, and an off-the-shelf Netgear wireless router used to connect an Internet enabled television and a home laptop (the one that does not connect).  Everything links w/o a problem except this one machine.    I've successfully linked other machines as well.

    There is, however, a Cisco wireless router which runs a separate work computer and VOIP phone for a connection to Work, but is POST the Netgear router so I figured it couldn't be the problem.  Additionally, when I shutdown and disconnect the Cisco,  I still cannot connect the home laptop.

    For these reason's, I am assuming that the problem lies with the Laptop itself.  Since I can't find a bug/virus on it, no re-directors, no expired antivirus programs, etc... I am going to try wiping and reloading the machine and see if that does the trick.

    I will post my results.......

    Author Comment

    Wipe and reload worked!

    Author Closing Comment

    Sorry this took so long to complete.  It turns out that McAffee AV had a known issue which was fixed via patch.  I ran across this on 2 other machines.

    LVL 82

    Expert Comment

    by:Dave Baldwin
    Glad you got it fixed.  Thanks for the points.

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