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Windows 7 clients randomly lose network connectivity

    質問

  • I've researched this as much as I can but am still having problems.  We have an office of about 20 users, all using relatively recent PC's connected to Gigabit network with a SBS 2011 server and a Server 2008 R2 database server.

    About a year ago, we started having problems at one end of the building with a couple users suddenly losing their network connection.  Randomly, the users PC would disconnect from the network.  Mapped drive letters inaccessible.  Yellow exclamation mark on the network status icon in the system tray.  Rebooting fixed it.  We soon discovered unplugging and replugging the network cable fixed it.  The problem spread to a couple other computers.  Tried using static IP addresses instead of DHCP thinking there were issues with DHCP leases (grasping at straws at this point), but same problem would reoccur.  Tried lowering the ethernet link rates to 100Mbit and that did help to alleviate the problem but not a solution as we need Gigabit speeds.

    Lately, our Server 2008 R2 database server started doing the same thing.  Just drops off the network.  Yellow exclamation mark.  Static IP address, and no connectivity (can't ping anything local or remote).  Unplugging the network cable and reinserting fixes it, for a while.

    Looking in the event viewer logs of the Win 7 clients and the server, does not show any "link down" events at all.  There is is always a event 1014, reporting some dns target could not be contacted, though I think that is because connectivity is lost.

    My research has shown this type of problem (same symptoms) have existed for a quite a while, but no one really has posted a cause or solution.  Some say disable IPv6 and disabling certain adapter properties like offloading.  I've disabled those on the adapter (mostly the client PC's have realtek ethernet), but no joy.

    What makes no sense to me is why, all the sudden, would this start happening?  The database server has worked flawlessly for almost two years.  Nothing changes on it.  We don't even do updates in it! 

    This weekend, I put an Intel Gigabit server adapter in the database server to replace the built-in Broadcom.  24 hours and still working, so fingers crossed, but what the heck?  

    Any help or ideas would be appreciated.

    2014年1月13日 15:46

回答

すべての返信

  • Hi,

    First, please help to clarify following questions:

    1. Please upload the topological graph about your network connection.
    2. Did these computers disconnected at the same time or they disconnect randomly themselves?
    3. What kind of switch you are using in this network?

    I consider that this issue can be caused by broadcast storm or the port negotiation between your client computer and switch.

    Broadcast Storm

    http://www.techopedia.com/definition/6270/broadcast-storm

    Once the problem happened, the easy way to know whether the broadcast storm is persists, please check the signal lamp on the switch are all flashing including the empty ones.

    Also, we can check the one-to-one connection between the problematic client and switch. We check this to determine that whether the issue is related to port negotiation. If you have the smart switch, you can check the port negotiation both on physical and protocol level.

    If we still fail to get the point of this issue, please also post back the results  of ipconfig /all on the problematic computer for our research.


    Kate Li
    TechNet Community Support

    2014年1月14日 7:29
    モデレータ
  • Hi,

    Have you taken time to check my suggestions?

    Any update, please get back to us for further plan.

    Look forward to your response.


    Kate Li
    TechNet Community Support

    2014年1月22日 14:17
    モデレータ
  • Hi, 

    Since there is no response from you, we considered that you have gotten what you want in previous post. 

    For further question, please don't hesitate to come back here and let's discuss again. 

    If you have any feedback on our support, please click here



    Kate Li
    TechNet Community Support

    2014年2月7日 7:09
    モデレータ
  • I am also facing same issue for last few days. I have 4 (48) port switches in my LAN. Some PCs from all switches are loosing network connection randomly. At the same time some PCs on the same switches are not facing any problem at all.

    So it doesn't seem to be a "broadcast storm" issue. I am still investigating about it.

    2015年1月28日 12:15
  • I am also facing same issue for last few days. I have 4 (48) port switches in my LAN. Some PCs from all switches are loosing network connection randomly. At the same time some PCs on the same switches are not facing any problem at all.

    So it doesn't seem to be a "broadcast storm" issue. I am still investigating about it.

    What brand switches do you have?  We wound up replacing the switches with new Dell 48-port Gigabit switches and the problem has been resolved. FWIW, our old switches were LINKSYS  48-port.  I don't remember the model number.
    2015年1月28日 12:50
  • I have D-Link web smart switches(DGS-1248T) 48 port switches.

    There are around 30 PCs connected to this switch. Only 8 PCs are experiencing this problem. Rest of them are fine. I removed 4 PCs out of these 8 and connected to another switch in the same LAN. Still same issue faced. It doesn't seems to be switch issue.

    Could it be some spyware or malware issue?

    2015年1月29日 13:56
  • Hi ,

    We have same problem .

    Following are the symptoms :

    1 : Hosts drops randomly across multiple switches (All Cisco 3750x), and on random vlans

    2: Drops take approx 5 min

    3 : Yellow exclamation is showed

    4 : Link between the Host and the switch are Up

    5: While drop is occuring we see in the switch ARP is incomplete

    6 : Eventlog does not show any indication of drops

    7 : Wireshark does not show any broadcast storms

    Anyone any ideas what we still can check ?

    Many Thanks ,

    Danny

    2015年2月7日 19:38
  • Hi @all did some one have a solution for that problem? Since some weeks we also have that problem on different Clients. Wireshark show no error, Client hold the IP but the LAN- Icon show limited connectifty... Idea´s ?
    2018年7月2日 14:36