I am having an intermittent problem with my network connection dropping out for no apparent reason. When it drops, I still see the lights blinking on the NIC card, but cannot pass packets even to the router. Windows does not report the connection or the cable as disconnected when this problem is occurring. When the issue occurs, I can't ping the gateway, do DNS lookups or pass any packets as far as I can tell. Ping tests all just time out when the problem is going on. The problem will persist until I disconnect and reconnect the CAT-5e wire, or disable and re-enable the NIC. As soon as I do one of those 2 things, connectivity immediately returns (and works for another hour or so).
I am running a legitimate copy of Windows 7 Home Premium 64-bit on an HP Pavilion. All of the latest Windows updates and the latest firmware drivers are installed. My Ethernet connection is a wired Local Area Connection with a static IP address, gateway and DNS. The IP address, gateway and DNS settings are accurate and work for several other computers here.
The Network Interface Card is a Realtek PCIe FE Family Controller (VEN_10EC / DEV_8136 / REV_05). NIC Power Management, Energy Efficient Ethernet, and Link Down Power Saving are all turned off. On the NIC, ARP/Large Send/IPv4,TCP,UDP Checksum/NS Offload, and Flow Control are all on. Receive Buffer Size on the NIC is 64Kb (512 buffers). Receive Side Scaling on. 128 Transmit Buffers. Interrupt Moderation is turned on. Magic Packet features are turned off. Optimal Performance enabled. NIC Speed and Duplex are set to 100mbps Full Duplex wherever possible (automatic was also tried). 802.1X authentication (EAP or PEAP) is disabled. Auto connection logic is disabled.
Connection routes through two switches into a Belkin router; other devices on same networks unaffected. Much of my data is stored on a Network Attached Storage device, with UNC shares mapped to drive letters. Other Windows, Mac and Linux devices connected to the same NAS device have no problems staying connected.
I have tried swapping out the CAT-5e cables for other cables, and even ran them through a cable tester to make sure they're working.
Network fixes I have attempted from the OS level so far include:
- Switching the dynamic port range to start at 10,000 and run for approximately 54,000 ports
- Systematically reviewing every running service to make certain that only the essential ones are on
- Disabling all NIC stacks except Client for Microsoft Networks, IPv4, File and Printer Sharing and Comodo
- Attempted connections with Comodo turned completely off and its NIC driver disabled
- Attempted rolling back the RealTek driver to an earlier one from the same family and device line
Using netsh I have tried the following settings:
netsh winsock reset catalog
netsh int ipv4 reset reset.log
netsh int ipv6 reset reset.log
netsh int tcp set global rss=enabled
netsh int tcp set global chimney=automatic
netsh int tcp set global autotuninglevel=disabled
netsh int tcp set global congestionprovider=ctcp
netsh int tcp set global ecncapability=disabled
netsh int tcp set global timestamps=disabled
netsh int tcp set global netdma=enabled
netsh int tcp set global dca=enabled
I have ruled out any malware, spyware, virus or trojan horse as a possibility after extensive scans with:
- MalwareBytes Anti-malware 188.8.131.520 (subsequently updated to latest DB)
- Kaspersky TDSSKiller
- Microsoft Antimalware Security Essentials
- Avira AntiVir
- Sophos SAR 15 SFX
- PrevX v3.0 CSI Free Edition
Here's the output from an IP Config command:
C:\>ipconfig /all Windows IP Configuration Host Name . . . . . . . . . . . . : User-HP Primary Dns Suffix . . . . . . . : Node Type . . . . . . . . . . . . : Hybrid IP Routing Enabled. . . . . . . . : No WINS Proxy Enabled. . . . . . . . : No Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Realtek PCIe FE Family Controller Physical Address. . . . . . . . . : 3C-D9-FE-ED-FA-CE DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes IPv4 Address. . . . . . . . . . . : 192.168.2.130(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : 192.168.2.1 DNS Servers . . . . . . . . . . . : 184.108.40.206 220.127.116.11 18.104.22.168 NetBIOS over Tcpip. . . . . . . . : Enabled
What could be the problem and how do I fix this?