What are the reasons for the automatic shutdown of the network card in CentOS7?

There are several possible reasons that could lead to the network card on CentOS 7 automatically shutting down:

1. Network adapter driver issue: It may be due to problems with the network adapter driver causing the network card to shut down automatically. You can try updating the driver or reinstalling the adapter driver.
2. Power management settings issue: In some cases, CentOS 7 may automatically disable network cards to save power. It is important to check the power management settings to ensure that the network card is not being turned off.
3. The issue with internet service may be due to misconfiguration or failure of the network service or related components, causing the network card to disconnect. You can try restarting the network service or rebuilding the network configuration file.
4. Issue of network conflict: If there are conflicts with IP or MAC addresses in the network, it may cause the network card to automatically shut down. It is important to identify and resolve these conflicts in the network.
5. Hardware malfunction: In some cases, automatic shutdown of the network card may be caused by hardware failure or damage. You can try replacing the network card or troubleshooting hardware issues.

It should be noted that the above is only one possible reason, and specific reasons will need to be further investigated and debugged based on the actual situation.