I have a SBS 2003 domain with approximately 30 client computers in our LAN. The majority of the clients are XP, but we have 4 Win 7 clients (mix of 32 & 64 bit). The SBS is the domain controller, DHCP, and DNS for all LAN computers. I have had no trouble with this setup for over a year. In the last 2 days, one by one my Win 7 computers have all started to experience a intermittent problem. They would seemingly lose connection to the server, to include all network resources and internet connection. All XP computers remain fine. To reconnect, sometimes the problem would fix itself, sometimes a logoff/logon was required, and sometimes a full restart was in order. I cannot determine any pattern to the connection loss, except that it has grown from rare and on one machine to frequent (5-8 times a day) and on all Win 7 machines. The machines are located throughout our operation, so a single faulty switch would not be the culprit, and also would not explain the effect only being on Win 7 machines. There is nothing helpful in the error logs. The growth curve of the issue seems to indicate propagation. I have made no changes to our hardware infrastructure and the only software changes would be regular Windows updates. I have searched forums extensively, but have found nothing helpful so far. Anyone have any suggestions or thoughts? Thanks, Scott

Hi, Can you ping to the default gateway when the issue happens? Also, some steps need to to taken to help us find out the culprit. 1, Turn off the firewall wall. 2, Make sure the DNS setting is corect. 3, Update the NIC's driver. 4, Check the Route Table by "route print" command. If you have any feedback on our support, please clickhere Juke Chou TechNet Community Support

0. I will have to test default gateway (which is router) ping. 1. I have now turned off the firewall on one of the Win 7 clients (though it worked fine for over a year with the firewall on) 2. DNS is automatic and gets set to the SBS which is setup correctly and has not changed 3. There are no updates available for the NIC 4. see below: IPv4 Route Table =========================================================================== Interface List 0x1 ........................... MS TCP Loopback interface 0x10003 ...00 18 8b fd 6e 83 ...... Broadcom NetXtreme Gigabit Ethernet =========================================================================== =========================================================================== Active Routes: Network Destination Netmask Gateway Interface Metric 0.0.0.0 0.0.0.0 192.168.0.1 192.168.0.104 1 127.0.0.0 255.0.0.0 127.0.0.1 127.0.0.1 1 192.168.0.0 255.255.255.0 192.168.0.104 192.168.0.104 10 192.168.0.104 255.255.255.255 127.0.0.1 127.0.0.1 10 192.168.0.255 255.255.255.255 192.168.0.104 192.168.0.104 10 224.0.0.0 240.0.0.0 192.168.0.104 192.168.0.104 10 255.255.255.255 255.255.255.255 192.168.0.104 192.168.0.104 1 Default Gateway: 192.168.0.1 =========================================================================== Persistent Routes: None

Hi, The route talble looks good. Now, follow the steps below to narrow down. 1, Ping Default gateway by IP address. (If ok, go the next step) 2, Ping a host name which in your subnet. If ok, try to use host name to access the internal resource. Eg, shared folders or Internal website. If ping is ok, but cannot access the resources, please uninstall NIC driver and reinstall, this will reset TCP/IP. 3, Ping an external DNS name to check whether the DNS works properly. This will tell us whether we can access internet and Publish DNS works. Juke Chou TechNet Community Support

So yesterday all 4 Win 7 machines worked great all day long. Today (approximately 10 minutes ago), all 4 lost connection at the same time. After roboot, at least one immediately lost connection again. I will follow the above steps with the next occurrence. Thanks

Results when connection down: 1. Gateway ip ping good 2. SBS Hostname ping fail, Navigate to network resource fail (did not reinstall NIC) 3. External DNS ping fail (used www.google.com and it returned "could not find host www.google.com") Possibly worth mentioning is the status in the Network & Sharing Center. The diagram indicates a good line between the Computer and the Local Domain, but a bad line (with X) between the Local Domain and the Internet. Next? This is becoming a major problem as users are starting to request an XP downgrade....which is opposite from the direction I am trying to move....

Hi, According to the test result, seems it is a DNS problem. Change to a public DNS server and test whether you can get Internet access. 8.8.8.88.8.4.4 If still no go, go to Control Panel\All Control Panel Items\Troubleshooting, and use the Network Troubleshooter to detect cause. If possible, post the troubleshooter report here. Juke Chou TechNet Community Support

So after experiencing the problem and changing the DNS to google as suggested, I can now: access the internet without a restart (cycled the network adapter disable/enable) ping www.google.com However, I cannot: access network resources ping SBS ip or name

Try to investigate if you have Denial of Service (DoS) attack or Distributed DoS - DDoS. Specially look at DNS attacks. You would receive large number of requests on port 53 UDP and TCP. You may need to install Network Monitor on your SBS server.