On the Internet, there are more than 23 million computers, these computers don't matter what they are models, what software is running, what software is used, can be concatenated into two categories: clients and servers.
The client is a machine accessing others information. When you type through the Post Office or other ISP, your computer is temporarily assigned an IP address, using this temporary ID card, you can get information in the Ocean of the Internet, when you disconnect, your computer The IP address is also retracted from the Internet.
The server is a machine that provides information that allows others to access, is often referred to as a host. Because people may access it at any time, it is necessary to connect to the Internet every moment as the host, has its own permanent IP address. To do this, you must not only set a dedicated computer hardware, but also rent expensive data lines, plus all kinds of maintenance costs such as rent, artificial, electricity, etc., will never be well affected. To this end, people have developed virtual host technology.
Using virtual host technology, you can divide a real host into many "virtual" hosts, each with separate domain names and IP addresses, with complete Internet server features. The virtual host is completely independent, in the outside world, every virtual host is exactly the same. The same is true, but the cost is big. Since multiple virtual hosts share a real host resource, each virtual host user has a hardware cost, network maintenance cost, and communication line costs, the Internet is really a network that everyone can use!
At present, many enterprises have established websites to use this method, not only, not only the costs of purchasing machines and rental special lines, but also do not have to worry about the technical issues of using and maintaining the server, do not have to hire specialized managers.
