We know, in the Internet has QianBaiWanTai host, in order to distinguish the mainframe, people give each host is assigned a special address, called the IP address. Through the IP address can visit to each host. The IP address of four parts, each part Numbers are not greater than 256 between the parts, using decimal divided.

2, what is a domain name?

From the Angle of ordinary users, domain names or marks and similar, if we want to find an enterprise wants to buy the product of the enterprise, the first to know the names of enterprises, then the domain name is enterprise in the Internet, such as CCTV WWWW. The domain is CCTV.com, when we are in the Internet browser typing this site, can see on TV or news, you can understand the domain, the characteristic is a global domain uniqueness, as our domain is www.cn49.com, then this world, so that the domain is precious, below is a professional personage to prepare, ordinary users see this, if you want to see if I don't stand in your way.

Technically, domain name is used to solve an Internet IP address of a problem. Although can through the IP address to visit each host, but want to remember so many withered the roughness numeric string is obviously very difficult, therefore, the Internet provides a Domain Name (.). Some parts of domain name also between the parts, using decimal divided. For example "site" the domain expert is cn49 ".com ", obviously better than the IP address memory domain. Before the domain and transfer protocol information and the type information constitute the host URL), such as the WWW site "expert" is "the host URL http://www.cn49.com". A complete domain consists of two or more than two parts, each part of the period between English. "to separate, last one." the right parts called top-level domain names (TLD, also known as the primary domain name), the last one. "on the left side as secondary domain (SLD), sub-domain left parts called level domain, by analogy, each domain control it to the next level of distribution domain, That is a technical term domain. However, because of the Internet has become the world's Internet domain are naturally become a social science noun. Internet domain is Internet network on a server or a network system of names in the world, no duplication, the domain name. Based on several forms of domain name in English letters and Numbers, is divided into several parts, such as IBM.com is a domain name, CHINADNS.com is an international domain. Both international and domestic domain, the world of Internet net up can be accurate. From the perspective of social science, domain name has become part of Internet culture.