Thousands of hosts on the Internet are distinguished by IP addresses. When everyone knows the IP address, it is difficult to find these numbers. Can you have some convenient form of our memory to visit each other? Under this requirement, we have DNS (domain name). It is because of the domain name system, so we visited Nanchang University's mail website, enter directly at the address: mail.ncu.edu.cn. CN: China EDU: Education Network NCU: Nanchang University MAIL: Mail. Otherwise, everyone has to remember the form of the following IP address every time you visit Nanchang University: 210.35.240.3. In contrast, is it easier to remember in the Mail.Ncu.edu.cn in front?
But for your computer, it only knows 210.35.240.3, mail.ncu.edu.cn is nothing meant. How can this contradiction solve? A server can be set specifically, its role is to find the corresponding IP address based on the domain name. So in the computer, the settings in the TCP / IP attribute are important to the settings of the DNS Server. DNS Server To set the correct, otherwise, you enter www.sina.com.cn, the computer does not know how much it is to query this corresponding IP address. For computers, I only know that the domain name is nothing. The DNS Server setting is also the same, there are two ways, one is manual input, static, requires network management to tell you. Another is that while dynamically obtaining an IP address, DNS Server is also dynamically obtained.
The IP address of the DNS Server of Nanchang University is: 210.35.240.2, IP address of the alternate DNS server: 202.101.224.68. That is to say, we need to access this server before accessing any website, and resolved the domain name as an IP address, and then proceed.
That everyone may ask, the domain name is what we will set, or how do you decide? This is the same as the IP address, it is necessary to apply. Can't set it yourself.
Let's introduce the structure of the domain name.
Top domain name
The domain name consists of two or more words, and the intermediate is separated by the point. The word on the right side is called a top domain name. Here are a few common top-level domain names and their usage:
.Com - for commercial institutions. It is the most common top-level domain name. Anyone can register the domain name in .com.
.NET - initially used for online organizations, such as Internet service providers and maintenance companies. Now anyone can register the domain name ended with .NET.
.Org - is a non-profit organization for a variety of organizations. Now, anyone can register the domain name of .org.
The national code is called the top domain name of the two letters, such as .cn, .uk, .de, and .jp, called national code top-level domain name (CCTLDS), where .cn is China's dedicated top domain name, which is registered with CNNIC management. The second-level domain name ended in the CN is referred to as domestic domain name. The rules and policies of the second-level domain name under the top-level domain name of the country are related to the policies of different countries. You should consult domain name registration agencies when registering, asking the relevant registration conditions and the terms related to registration. Some domain name registrars provide registration of national code top-level domain names in addition to the registration services that are ended with .com, .net, and .org. ICANN does not have special authorized registrars to provide registration services for the top-level domain name of the national code.
secondary domain
The next level of the top-level domain is the second-level domain of our two. DomainPeople.com, domain registrants provide a secondary domain name in the top domain name ended with .com. The domain name may also be Something.Domainpeople.com. In this case, Something is called a primary name or a domain name.
Who is an international domain name management agency
ICANN is a non-profit organization in recent years, instead of NSI's non-profit organization, which includes managing Internet domain name and address systems. Information about ICANN can be queried in the URL http://www.icann.org. Since all levels of domain names on the Internet are managed by different institutions, each mechanism management domain name and the rules of domain name naming are also different. But the domain name is also a common rule, mainly the following:
First, only the following characters can be included in the domain name:
26 English letters
2. "0, 1, 2, 3, 4, 5, 6, 7, 8, 9" ten numbers
3. "-" (Conjunction in English)
Second, the combination rules of characters in the domain name:
1. In the domain name, do not distinguish between English letters
2. For a domain name, it is a certain limit for the rules of the CN name name name:
