How to solve the issue of CentOS7 network card not starting up.

If the network card on CentOS 7 fails to start, you can try the following troubleshooting methods:

1. Check the status of the network card by using the command ifconfig or ip addr show to make sure the network card is functioning properly.
2. Restart the network service: Try using the command “systemctl restart network” or “systemctl restart NetworkManager” to restart the network service and see if it resolves the issue.
3. Check the network card configuration: Verify the settings in the configuration file /etc/sysconfig/network-scripts/ifcfg- to ensure they are correct. You can use the command cat /etc/sysconfig/network-scripts/ifcfg- to view the configuration information.
4. Check the network connection: make sure the ethernet cable is connected properly and that the router or switch is functioning correctly. You can try swapping out the ethernet cable or connecting to a different port.
5. Check drivers: Verify that the network card drivers are installed correctly and compatible with the operating system. You can use the command lspci -k to view detailed information about the network card.
6. Update your system: If the above methods are not able to solve the issue, consider updating your system to the latest version. This may help fix some network problems caused by system bugs.

If none of the above methods can solve the problem, it may be caused by hardware failure. It is recommended to contact the hardware manufacturer or technical support for further diagnosis and repair.