Sometimes the LAN is on, sometimes it is not, and the LAN is not available

First of all, you should check the line of the intranet, according to your description, the switch may be the problem, try to change it to see if the problem still exists.

If the computer display is physically disconnected, that is, the network card display is disconnected, it must be a problem with the hardware connection part, focus on checking the hardware part.

If there is no superficial phenomenon, but you can't access the network, and the network connection icon in the task blue does not indicate that it is disconnected, it should be an ARP virus, bind ARP on the server, or a VBS script (bind ARP) from the Internet, and it can be solved by tying it on the client.

What should I do if the LAN connection is not working? Still confused! Let me give you a detailed introduction to the solution to the LAN failure! Hope it helps!

LAN is not available for resolution:

1. Inspection

The inspection here refers to the inspection of the cable, that is, the cable between the computer and the network interface.

In the case of a small 10 100 network, only open circuits, short circuits and cabling are sufficient, and in the case of Gigabit Ethernet, there is also a need to check for crosstalk and impedance in the cables.

2. Confirmation

Confirmation, which lets you confirm that you are connected to the switch.

Once you've confirmed that it's not the individual computer causing the problem, you connect the portable network tool to the office line, check if the link can be established, and then check the port configuration again to make sure the port is available and configured with the correct VLAN.

3. Application

After "confirming" and establishing the link, use the tool to request a DHCP address from the server. You should ensure that the assigned address matches the corresponding subnet; Verify the subnet mask; Confirm the default gateway and DNS server address.

If it fails to get a response from the server, it should be able to detect the corresponding subnet by analyzing the broadcast traffic. Check the switch ports that the tool is connected to with the Cisco Discovery Protocol (CDP) report obtained from the switch, and confirm the subnet configuration.

4. Ping

Ping devices on the network.

After obtaining the DHCP address, you can use the tool to ping a device outside the LAN (it is recommended to directly ping a ** home page address). This step will help you confirm that the DHCP specification is configured correctly and that the network data is being sent correctly through the route.

5. Inspection

Check, the test is the speed of the duplex mode setting.

In fact, after the fourth step, if the network is not connected, you can think about whether the previous four steps are missing, and if not, please consider this step again.

Link performance failures, such as duplex pattern mismatch, speed mismatch, and statically configured IP addresses, can only be detected. Therefore, I recommend that you use a tool with the detection function for the network management to detect. If a duplex pattern mismatch is detected, confirm that both the computer and switch ports are set to the automatic protocol.

Once all these parameters have been verified, the link between the computer and the network can be canceled. If the fault persists, you may need to use a more sophisticated network diagnostic tool.

As an administrator, these network problems should be a very small pediatric matter, and this tutorial is mainly for network administrators, but because the article is easy to understand, you can also learn to do it if you are interested.

The reasons and solutions for LAN failure are as follows:

1. The guest account is enabled on the computer, which causes the LAN to be unusable. Open the Control Panel and go to the Administrative Tools option, and in the Local Security Policies section of the page, select the Local Policies and then User Rights Assignment options. Finally, deleting the guest account in "Deny access to this computer from the network" will solve the problem.

2. The local connection is disabled, resulting in the LAN being unusable. Right-click and select the "Local Connection" option and click "Enable" to resolve the issue.

3. Computer intrusion virus, resulting in the LAN cannot be used. Upgrade the computer virus database security mode and then perform a full antivirus operation to solve the problem.

4. Contact computer after-sales service** for consultation and maintenance of problems.

In this case, the signal is generally attenuated, so it can be connected, but the signal is relatively weak. So I can't get on the Internet.

The reasons may be: 1. It is caused by the distance of the network cable.

2. It is caused by the poor quality of the network cable.

You check if the network cable is more than 50 meters. If it does not exceed, the general reason is the quality of the network cable. Please use double-shielded or all-copper network cables.

It's set up. Mistake. Suggestion. You.

From the new settings.

That's it. If not.

OK. Send a picture.

Come and consult. And.

There is 1 more. It's yours.

The dos is not set.

So there is. Possible.

Internet. Not easy to implement.

If it's a land-based rover.

Or possibly. Land Rover.

Caused by not being connected to the network. becoming.

Let's talk about how it doesn't work, so as to prescribe the right medicine. Let me ask you a few questions first, on what basis do you judge that your IP address is not set up, and is the local connection connected?

Is it because the online neighbor can't be opened? You can see if the guest user is blocked in Group Policy