Solve both Internet access and xshell Problems

Solve both Internet access and xshell Problems
First of all, we need to note that the Network in our school is free, whether in the lab or in the dormitory, so the Internet is allocated IP addresses based on the Mac address, so after I installed centos in VirtualBox, if you want to access the Internet, you need to change the mac address of VirtualBox to the same as that of my laptop, but xshell cannot be connected at this time. If you do not change the mac address of VirtualBox, if you use centos's own IP address, you can use xshell to connect, but you cannot connect to the Internet. After searching, you can find that you can set two network adapters, one for accessing the Internet, one block is used for xshell connection. For example:

After the system starts, it automatically obtains the/etc/sysconfig/network-scripts/ifcfg-eth0 that needs to be modified, and changes ONBOOT = "no" to ONBOOT = "yes ".