Problem Description:
Equipment used : a laptop, a network cable,
problems with win11 system : there is no problem with WiFi, and the Internet is normal. But the network cable does not work. After plugging in the network cable, the lower right corner is not connected, and the Internet cannot be accessed: I
tried ipconfig on the command line, and the IP and subnet mask of the Ethernet network card are very abnormal, and the IP address shows 169.254.XXX .XXX (normally it should be 192.168 on my side). Then the subnet mask is wrong, it shows 255.255.0.0 (normally it should be 255.255.255.0). Then the default gateway directly does not. If something is wrong, the same network cable can be used normally when it is plugged into another computer. If there is no problem with the network cable, it should be a problem with the computer.
solution:
Settings - Network and Internet - Advanced Network Settings - More Network Adapter Options - Right-click on the wired network card - Diagnose and
finally find that the DHCP service is not enabled, just choose to repair (because the wired network card has been repaired here , the picture below is the network card of the virtual machine)
Summarize
1. Windows network diagnosis is a good thing. If you can’t connect to the Internet, you can try the network diagnosis first. It will give you feedback about the problem with the network card and repair it.
2. About 169.254.XXX.XXX:
169.254.XX is the IP address automatically assigned to the client by the Windows operating system when the lease of DHCP information fails. Due to network connection problems (network cable problems), DHCP server (actually Modem, router, or host that provides shared Internet access) problems, etc.), the DHCP information lease fails.
The distribution of IP169.254.XX may make the client (your own computer, set "automatically obtain IP") and the local area network gateway (Modem, router, or host that provides shared Internet access) to be located in different network segments , but cannot communicate with the gateway, resulting in the inability to access the Internet.
Check the network card IP configuration
1. [Right click] —> [Network and Internet Settings]
2. The network cable is generally [Ethernet] (there may be a name like [Ethernet 2], the specific name of the network card depends on your actual situation)
Look at the IP and DNS settings of the network card. By default, both should be set to automatic (DHCP), and nothing is set. As shown in the picture below: (If you use it in daily life, all of them will default to automatic DHCP)
However, if you usually use the office network or intranet for office work, you will generally configure these two items. The specific configuration is set according to the regulations of the company or unit. If the setting is wrong, it will also cause you to be unable to connect to the Internet.
