I have encountered a very strange issue at a client's office and I am completely out of ideas as to what might be causing it. The infrastructure is as follows:
- HP server running MS Small Biz Server 2003 (server running DNS, DHCP, domain controller, active directory)
- 7 workstations all running XP Pro joined to the domain
- Comcast cable internet
- 3com wireless router
- 16-port Linksys switch
One day last week the client reported that all computers and server had lost the ability to browse websites. They could ping out and resolve host names (DNS working) but could not actually browse sites. Connectivity to their server was not affected as they could still access network shares and server applications. I started troubleshooting by calling Comcast; ruled that out as I could hook a laptop directly to the modem and browsed without problems. Verified that the router was working correctly and that all services were running properly on server.
Eventually what we determined is that when certain PC's are plugged into the switch, browsing ability is lost. There are 2 particular PC's that cause the problem. It cannot be a chattering NIC as only web browsing is affected. Access to server continues to function without problem. As soon as these computers are unplugged from the switch (or disconnected from wireless) browsing is restored. I scanned both computers for viruses - 1 minor trojan was found on one; the other was clean. I am at wits end on this issue. Hoping someone can offer suggestions. Something has to be running on these computers that are causing this problem, but I don't know what. Everything was working fine then all the sudden this started. Any ideas? Thanks! I will be happy to provide more info if necessary.
- HP server running MS Small Biz Server 2003 (server running DNS, DHCP, domain controller, active directory)
- 7 workstations all running XP Pro joined to the domain
- Comcast cable internet
- 3com wireless router
- 16-port Linksys switch
One day last week the client reported that all computers and server had lost the ability to browse websites. They could ping out and resolve host names (DNS working) but could not actually browse sites. Connectivity to their server was not affected as they could still access network shares and server applications. I started troubleshooting by calling Comcast; ruled that out as I could hook a laptop directly to the modem and browsed without problems. Verified that the router was working correctly and that all services were running properly on server.
Eventually what we determined is that when certain PC's are plugged into the switch, browsing ability is lost. There are 2 particular PC's that cause the problem. It cannot be a chattering NIC as only web browsing is affected. Access to server continues to function without problem. As soon as these computers are unplugged from the switch (or disconnected from wireless) browsing is restored. I scanned both computers for viruses - 1 minor trojan was found on one; the other was clean. I am at wits end on this issue. Hoping someone can offer suggestions. Something has to be running on these computers that are causing this problem, but I don't know what. Everything was working fine then all the sudden this started. Any ideas? Thanks! I will be happy to provide more info if necessary.
