Nic fault-two cases

Editor's note: In the network system, although the network card is small, it is not enough if it is missing. These two articles talk about The Troubles caused by network cards. I would also like to remind you that if there is a problem with the network, you should not only consider the switch or something. Maybe your bad network card is secretly enjoying it.
Attackers cannot access the Internet.

In the usual network management work, many network faults occur, and of course many network card faults occur. In many cases, either the system cannot find the network card or the System Protocol configuration is invalid, but this is a little special!
Recently, an office operating system in our company is a Windows ME microcomputer. The NIC configuration, Protocol configuration, and IP address are all correct, but you cannot access the Internet.
First enter the MS-DOS mode, use the IPCONFIG command, view the NIC configuration, IP address, subnet mask, gateway are correct, you can Ping your own IP address, gateway, DNS server, and Web server. Open IE, enter the domain name address of the master WEB server of the unit, and then display "Web address Found" in the IE status bar, and then "Open WEB page". Then, wait for a long time, "This page cannot be displayed" is displayed ".
Since the Web address has been found, it indicates that DNS resolution is correct. To ensure that no problem occurs and return to the DOS status, use IPCONFIG/ALL to view DNS and WINS. Enter the IP address of the master WEB server in IE, and the same error message is displayed.
Check the configuration of IE and whether the proxy server and trusted site are set. No problem is found! And the machine does not have any network firewall installed. I tried to use FTP again. When there was a welcome word from the FTP server, it paused for a long time and finally the report was not connected. I think it may be a problem of connection latency. Back to DOS, Ping the gateway 50 times and find the packet loss rate is 14%.
This may be a hardware problem. It may be a problem between the NIC, twisted pair wires, and switches. To solve the problem faster, I used a laptop to connect the twisted pair wires that were unplugged from the desktop, the result is normal. At this point, the problem is clear, it must be a problem with the network card. The network adapter does not completely lose its functionality, but the loss of data packets leads to network connection latency and the connection cannot be completed.
Take a screwdriver, remove the chassis, re-plug the NIC, and restart the machine. Everything is normal. So far, troubleshooting. (Wang Xuefeng)

Inside the story that the network speed is too slow

Our company adopts the fiber-optic broadband Internet access method. Through the network structure of a M switch to the office building, the desktop interface can reach M bandwidth. The speed is not enough-fast! A few days ago, the company configured a Pentium 4 brand machine for a business department, but because the brand machine itself is not configured with a nic, so the company leaders asked me to buy a nic, of course, the price cannot be too expensive.
Soon I bought a common 10/100 M Adaptive network card from the computer market and got the company. The NIC installation process is very simple. Windows 2000 successfully identified this Nic and installed its own driver. Next, start network configuration. First, set the IP address, gateway, and DNS as required in the network configuration of Windows 2000, and then restart the computer.
At this moment, the problem arises. Although the network can be connected successfully, but the speed is very slow, even a web page can not be opened normally, often half of the transmission report transmission error termination of transmission. Ping the DNS server and find that the packet loss is very serious. Based on my past experience, it is likely that there is a line problem. Because the wiring of the entire office building is set up in a unified manner and other departments are using it normally, there should be no problems with the lines in the wall. I began to suspect that the line from the interface on the wall to the host had interference, or there was a problem with the line. To solve electrical interference, I shut down all electrical appliances around the line, but the problem persists. In order to verify whether there is a problem with the line itself, I took out the laptop I CARRIED WITH ME, set the network configuration according to the Regulations, and access the network after the restart, everything is normal, the download speed can reach 80 kbps or more. In this case, the problem must be the computer itself. The network can be connected, indicating that the protocol settings should be correct. Is it a hardware problem? Replacing the NIC with a PCI slot does not solve the problem. So far, we can say that all the methods we can think of have come up with, that is, the problem cannot be identified.
At this time, I occasionally opened the NIC setting interface and saw the NIC speed setting. The default setting is 10/100 M Adaptive. Is it related to this? I manually set the NIC to 10 M. After the network is restarted, the access speed is much faster than the general dialing speed. However, as the status is limited to 10 MB, there is still a considerable gap with MB.
At this point, the cause of this network failure is finally found out that the quality of the original network card is not good (because the picture was cheap, JS sold me a poor quality network card ). All the Office offices use cisco's 10/100 M Adaptive System, and the wiring fully complies with the M Standard. However, due to poor network card quality, unable to adapt to the M line, resulting in serious data packet loss, resulting in slow speed.
After finding the cause, I immediately returned to the Computer City and explained my intention to the computer store owner. After listening to my explanation, the boss had to change a good Nic for me. (LU Wenxiu)