What if the network connection of the Ubuntu system is abnormal?

What if the network connection of the Ubuntu system is abnormal? -- Linux general technology-Linux technology and application information. For details, refer to the following section. My host is in the XP3 and Ubuntu9.04 dual system. The network cable is routed and then routed through the vswitch. When XP3 is used, the IP address is automatically obtained and cannot be accessed, therefore, you can only access the Internet by changing the IP address of the local machine to a self-configured IP address. However, I cannot access the Internet when I use the Ubuntu system. Because I am a newbie and don't know how to change the IP address, I changed it like this: Select Automatic (HDCP) as the IPV4 setting method and only the address. DNS server: 202.96.128.166, 202.96.128.86. In this way, after the Ubuntu system is started, the system can access the Internet after it is started, sometimes it will not work, and sometimes it will be disconnected when it is mounted, which is too unstable. However, it is normal to use XP, and the Internet can be accessed on the machine. What should I do?