Two Methods for changing the NIC em back to eth after CentOS 6.4 is installed

Today, I installed CentOS 6.4 On the Dell R710 server using mini. After the restart, ifconfig can only see one local loopback address. Check the NIC configuration file under/etc/sysconfig/network-scripts/, and the results do not find a configuration file like ifcfg-eth0, but there is more ifcfg-em1 and ifcfg-em2 ..... these configuration files. I did not understand why it became em, so I found some materials. There are two ways to modify the eth form.

Recommended reading: After CentOS is installed, ifconfig cannot display the NIC

As follows!

First:

The following line of information is displayed in dmesg:

Kernel: udev: renamed network interface eth0 to em1

The original device management process of udev changed the default eth0 to em1 during the boot process. In fact, em1 corresponds to the original eth0 Nic of the system; because I did not configure the network during mini installation, the system does not activate the NIC by default, so ifconfig cannot see any Nic; you only need to change the parameter ONBOOT = no to yes in/etc/sysconfig/network-scripts/ifcfg-em1, and then the service network restart Nic em1 appears!

I always feel that the NIC code of Linux is not used to em1. It is also possible to restore it to the familiar eth0. Adjust the NIC naming rule configuration file of udev.