What is a Uniform Source Locator (URL)

Internet is an ocean of information, but where is this information stored? In fact, these information are stored in computers called "sites" all over the world, and each site is maintained by the unit that owns the site, and the above information is released by the unit that maintains the site, which is also called "web page".

In order to distinguish each site, each site must be assigned a unique address, which is called "IP address" and IP address is also called URL (Chinese means "Uniform Resource Locator"). An IP address consists of four numbers from 0 to 255, such as 202. 1 16.0.54, but these numbers are comparative. So, someone invented a new method to replace this number, that is, the "domain name" address. A domain name consists of several English words. Www.jnu.edu.cn, for example, has certain significance, in which cn stands for China, edu stands for education, jnu stands for Jinan University, and www stands for World Wide Web (or WorldWideWed). The whole domain name together represents Jinan on China Education Network.

Domain name address and digital IP address are actually the same thing, but they are different in appearance. When visiting a website, you can enter the digital IP address of the website or its domain name address. There is a problem that the domain name address is converted from the corresponding IP address. This information is actually stored in a computer called Domain Name Server (DNS) at the ISP. When you enter a domain name address, the domain name server will search for its corresponding IP address. Website addresses can be found in magazines, newspapers and books about computers, and there is more information about website addresses on the Internet. From now on, you can collect some domain names and addresses of websites you are interested in.

The domain name system of the Internet is set to facilitate the interpretation of the IP address of the machine. Domain name system adopts hierarchical structure, which is hierarchical according to geographical domain or institutional domain. In writing, points are used to separate all levels and divide them into hierarchical fields. In the address representation of the machine, from right to left, the highest domain name segment, the second highest domain name segment, etc. The leftmost field is the host name. For example, in bbs.jnu.edu.cn, the highest domain name is cn, the second highest domain name is edu, the last domain name is jnu, and the host name is bbs.