Illustrate the functions of DNS. What are the main functions of DNS

The main function is to convert the domain name that is easy for people to remember and the IP address that is not easy for people to remember. The network host that executes the DNS service above can be called a DNS server. Basically, we usually think that DNS just translates the domain name into an IP address, and then uses the IP address to connect (commonly known as "forward resolution").

In fact, the ability to convert IP address to domain name is also quite commonly used, and when login to a Unix workstation, the workstation will do a reverse lookup to find out where you came in from (commonly known as "reverse resolution"). A domain name consists of two or more words, separated by a dot. The rightmost word is called the top-level domain.

Here are a few common TLDs and how to use them:

com - for commercial establishments. It is the most common top-level domain. Anyone can sign up. .com format.

net - was originally used by network organizations, such as Internet service providers and maintenance providers. Now anyone can sign up to. .net.

org – is for all kinds of organizations, including non-profit organizations. Now anyone can sign up to. org.

Country** consists of a two-letter top-level domain such as: cn, .uk, .

de and. JP is called the Country Level Domain (ccTLDS), where. cn is a top-level domain for exclusive use in China, and its registration is managed by cnnic.

The second-level domain name ending in cn is referred to as the domestic domain name. The rules and policies for registering second-level domain names under ccTLDs are related to the policies of different countries. You should check with your domain name registrar at the time of registration to find out the relevant registration conditions and terms related to registration.

Some domain registrars offer in addition to: com, .net and.

In addition to the registration service of domain names ending in org, it also provides the registration of country** top-level domains. ICANN does not specifically authorize registrars to provide registration services for ccTLDs.

The next level of the second-level top-level domain name is what we call the second-level domain name. , the domain name registrant is here. A second-level domain name is provided in the top-level domain name ending in com. The domain name form may also be.

What does DNS mean and what is it for.

DNS is the name server.

Once you enter it, the DNS translates this address into an IP address and finds the server.

In addition, DNS also automatically pre-stores more popular web pages to speed up browsing.

The function of DNS is to resolve ** to IP address. For example, if you tell someone that the zip code of my current place is 0371, others will know that you are in Zhengzhou when they check it, and DNS is the function. Good luck with your exams.

The DNS Domain Name System (DNS) is used to resolve domain names into IP addresses, and the domain name and IP address are linked together for service, so that you don't have to enter an IP address, but by entering **access**.

Each IP address can have a hostname, which consists of one or more strings, separated by a decimal point. With a hostname, don't memorize the IP address of each IP device, just remember the hostname that is relatively intuitive and meaningful. That's what the DNS protocol does.

The main functions of DNS include the following three:

Namespace: Define a namespace that includes all possible host names.

Domain name registration: Guarantee the uniqueness of each host's domain name.

DNS advantages:

The full name of DNS is Domain Name Server, a program that stores a table of domain names and corresponding IP addresses to resolve the domain name of messages.

A domain name is the name of a computer or group of computers on the Internet that identifies the computer's electronic location (and sometimes geographic location) during data transmission. A domain name is a string of names separated by dots, usually containing the name of the organization, and always includes a two- or three-letter suffix to indicate the type of organization or the country or region in which the domain is located.

It does not take a long time to resolve the domain name, because Internet access providers, such as Beijing Telecom and Henan Telecom through Sunshine DNS, usually cache a lot of DNS records of domain names in their DNS servers, and then make network allocations according to the user's location.

In this way, when the user of the access provider wants to open a web page, the server of the access provider does not need to query the domain name database, but directly uses the DNS records in its own cache, so as to speed up the user's access. This is its greatest advantage.

DNS is a service that links domain names and IP addresses, with a DNS server bend to do respect, you don't need to enter an IP address to access a**, you can access by entering**Hu Qing.

In the following description of the basic functions of DNS, the error is ().

You must provide a namespace for all possible node names.

Each host must be assigned a name that is unique across the network.

Each user must be informed of the IP address of all DNS.

It is necessary to provide a mechanism for the user at the head of the chain to effectively complete the translation of the hostname and the IP address of the network.

Correct answer: c

DNS resolution process:

1.The client stool spine makes a DNS request and sends the request to a local nameserver.

2.When the local nameserver receives the request, it will query the local cache first, and if there is such a record, the local nameserver will directly return the query result.

3.If the local cache does not contain the record, the local nameserver sends the request directly to the root nameserver, which then returns the address of the primary nameserver of the queried domain (a subdomain of the root) to the local nameserver.

4.The local server then sends a request to the name server that returns to the next step, and then the server that receives the request closes the coarse query for its own cache, and if there is no such record, returns the address of the relevant subordinate name server.

5.Repeat step 4 until you find the right record.

6.The local name server saves the returned results to the cache for next use, and also returns the results to the client.