One trick to solve the problem that the switch device cannot access the network

With the development of China's switch industry, it also promotes the improvement of its functions, but there will also be many problems in the use process, here we mainly analyze the situations where the network of the switch device is inaccessible. A switch is one of the core hubs in the LAN for data exchange and transmission. Its working status is directly related to the data transmission stability of the LAN network.

However, during a long period of work, the switch equipment is prone to one or more problems. Once a switch encounters a problem, many people often do nothing. In fact, most of the time, we only need to simply restart the switch device to solve most of the switch status faults. This is not the case. I encountered a fault that could not be accessed by the network. It took a long time to find the specific cause of the fault when solving the fault, finally, I restarted the switch device by accident and solved the network failure. Now, this article will restore the failure for your reference!

Some workstations cannot access the Internet

Early in the morning, when I was just on the way to work, the harsh cell phone rang. the comrades in a certain department of the organization said that my workstation could not access the Internet normally, the internal Web server of the Organization cannot be accessed normally. Some other colleagues reported to the author that their workstation cannot access the LAN of the Organization normally.

The LAN structure of the organization is actually very simple. The common workstations on each floor are connected to their respective L2 switches, all L2 Switch devices are connected to the core switch of the LAN through stacked connections. When I arrived at the office, I immediately opened my workstation and tested the network connection. I found that the network connection was normal. Why? To further check the network connection status, I immediately open the local system running dialog box and enter the string command "ping10.176.6.1", where 10.176.6.1 is the LAN gateway address, from the command execution result shown in returned 1, we found that the gateway is working normally. During the holidays, another network administrator of the organization usually closes all work subnets other than the central data center on the core switch device. Isn't these work subnets yet activated?

In order to check whether the working status of other work subnets is normal, the author immediately brought related tools and laptops, quickly arrived at the fault site. Find any workstation in other working subnets that cannot access the Internet, click the "Start"/"run" command, and in the displayed system running dialog box, enter the string command "cmd ", click OK to switch the system status to the doscommand line status. At the command line prompt in this status, enter the string command "ipconfig/all" and click the Enter key, I found that the IP address, gateway address, DNS server address, and network mask address displayed on the result interface are correct, and no suspicious information is found. Why is the workstation unable to access the lan network properly when the Internet access settings are correct?

In-depth exploration of the reason why the Internet access is unavailable

Is there any problem with the faulty workstation? With this in mind, the author immediately opens the running dialog box of the system, executes the "ping127.0.0.1" string command in it, and then returns a command similar to "Replyfrom127.0.0.1: bytes = 32 time <1 msTTL = 128 "indicates that the local loop address" 127.0.0.1 "can be pinged normally, this also means that the TCP/IP communication protocol of the faulty workstation is working normally.

In order to verify whether the NIC device of the local workstation is working normally, the Ping command is used to test the connectivity of the NIC device address of the local workstation. The Ping command is successfully executed, this also indicates that the NIC device of the faulty workstation is working normally. Next, I tested the connectivity of the LAN gateway address in the faulty workstation. The test result is "Requesttimedout" (2 ), this indicates that there are some problems with the network connectivity between the local workstation and the LAN gateway device. Is it true that there is an accident with the LAN router or gateway device? However, I think this is not possible because I have tested the connectivity of the LAN gateway address on my workstation before coming to the site of the faulty workstation, the system can be pinged normally. Check the taskbar icon on the desktop of the faulty workstation system and find that the local connection icon is in the "m connected" status ".

Is it possible that this faulty workstation is infected with a network virus, or is it possible that this workstation has installed and enabled a professional firewall program, which causes the connection to the Internet to be temporarily disabled by the firewall program? To eliminate these possible factors, I immediately took out my laptop that I carried with me. The computer was tested to be able to access the Internet normally, unplug the network cable connecting to the faulty workstation and re-insert it into the laptop. Then, open the system running dialog box of the laptop, and execute the string command "ping10.176.6.1" in it ", the target gateway address cannot be pinged normally. Later, I double-click the "local connection" icon in the tray area of my laptop system. From the local connection Status dialog box that appears later, I found that my laptop can only send data packets to external devices, however, data packets cannot be received from outside, which indicates that the failure of network access has nothing to do with the faulty workstation system.

As a last resort, I took my laptop to a department next to the faulty workstation, inserted a network cable into my laptop, and then executed the string command "ping10.176.6.1 ", I found that the test result was normal, and then I immediately conducted a network access test. The result shows that the network access operation has become normal. It is reasonable to say that all the Internet points connected after a laptop computer belong to the same working subnet. Why do some Internet points work normally while others cannot? Where exactly is the problem? Return to the faulty workstation and I can see that when the network cable is inserted into the interface of the corresponding switch device, the status information displayed on the local connection icon at the system tray area is still "m connected", but the network connection is still unsuccessful when accessing the Internet!