explain

Domain name resolution English name: DNS (domain name resolution)

After the domain name is registered, it only means that you have the right to use the domain name. After the domain name resolution, the domain name can play its role. The resolved domain name can be used as the website to visit its own website, or as the suffix of the e-mail address. Therefore, "domain name resolution" is a necessary link to use the domain name.

How can I see the content of my website after registering a domain name? In a professional term, it is called "domain name resolution".

People are used to memorizing domain names, but machines only recognize each other's IP addresses. Domain names and IP addresses are one-to-one. The conversion between them is called domain name resolution. Domain name resolution needs to be completed by a special domain name resolution server, and the resolution process is automatic.

Example

If you visit a website, you will enter the website www.example.com and the corresponding website page will be displayed. What is this situation like in the background? The server where the website content is located has only an IP address. Bind the domain name with the IP address (that is, domain name resolution), guide visitors to obtain the web page content in the website server, and then you can enter the website address to visit the website.

If you use an e-mail, you need to indicate the relationship between your e-mail address and the e-mail server on the Internet. Only after the domain name resolution can you and the other party send the e-mail correctly, and the e-mail can find your e-mail correctly.

Common types

1. A Record resolution

Select "A" as the record type; The record value is filled in the host IP address provided by the space provider; MX priority does not need to be set; The TTL is set to 3600 by default.

2. CNAME record resolution

The method of CNAME type resolution setting is basically the same as that of record type A, where the record type is modified to "CNAME" and the record value is filled in the server host address.

3. MX record resolution

MX record resolution is used for mailbox resolution. Select MX as the record type, select Universal as the line type, or add records with three line types of Telecom, Netcom and Education Network at the same time; For the record value, fill in the server IP address or alias address provided by the postmaster; The TTL can be set to 3600 by default. The MX priority should be filled in the data required by the post office provider, or 10 by default. When there are multiple MX records, the priority should be set to different data.

Noun resolution

Universal domain name resolution

Universal domain name resolution refers to The domain name resolves to the same IP. Add any sub domain name in front of the domain name to access the WEB address pointed to. If the domain name is a.com, that is to say, the . a.com all resolve to the same IP address. For example, setting * *. a.com will automatically resolve to the same IP address as a.com.

Intelligent domain name resolution

In addition to the general basic DNS resolution function, domain name intelligent resolution can also automatically identify the source of the browser, and resolve the same domain name intelligent DNS to the IP address of Netcom or Telecom of the two-way machine, so as to access your website nearby.

MX record

For routing records, users can point the mail server under the domain name to their own mail server, and then control all mailbox settings by themselves. You only need to fill in the IP address of your server online to transfer all the mail under your domain name to the corresponding mail server you set yourself.

CNAME record

CNAME is also a common record category, which is an alias record (Canonical Name). When the DNS system queries the name on the left side of CNAME, it will turn to the name on the right side of CNAME and then query until the last PTR or A name is traced. A response will be made after a successful query, otherwise it will fail. This record allows you to map multiple names to the same computer. Unlike record A, CNAME alias records can be set with a description of a domain name, not necessarily an IP address. Usually used for computers that provide both WWW and MAIL services.

TTL value

The full name is "Time To Live", which simply means the time when DNS records are cached on the DNS server.

A Record

The IP pointing A (Address) record of the WEB server is used to specify the IP address record corresponding to the host name (or domain name).

URL forwarding

Forwarding function: If you do not have an independent server (that is, you do not have an independent IP address) or you have a domain name B, you can access the content of domain name B when you want to access domain name A, then you can use URL forwarding to achieve this. URL forwarding can be forwarded to a directory or even a file. Cname is not allowed, which is the main difference between url forwarding and cname. Domain name A record: A (Address) record is the record corresponding to domain name and IP. Domain name alias record: alias (CName, Canonical Name) record, which is the record corresponding to the domain name and its alias. Dynamic domain name resolution: The IP corresponding to the domain name in record A is a static IP. Resolving the domain name to a dynamic IP is called dynamic domain name resolution. Domain name service providers generally only provide A records for free, not dynamic domain name resolution for free.

Domain name resolver

The domain name resolver is the intermediary that converts the domain name to the IP address of the host. Usually, when you go online, you type in a domain name address, and the computer will first search the DNS server for the corresponding IP address. After the server finds the corresponding value, it will return the IP address to your browser. At this time, the browser sends a browse request based on the IP address, so that the domain name addressing process is completed. The operating system will save the corresponding values of your commonly used domain names and IP addresses. When you browse frequently visited websites, you can directly extract the corresponding IP addresses from the DNS cache of the system to speed up the connection to websites.

Domain name resolution software

DNS system is driven by various DNS software, including BIND (Berkeley Internet Name Domae most commonly used namedaemon. DJBDNS (Dan J Bernstein's DNS implementation) MaraDNS NSD (Name Server Daemon) PowerDNS, etc. DNS implements a hierarchical namespace by allowing a name server to "delegate" part of its name services (known as zones) to child servers. In addition, DNS provides some additional information, such as system alias, contact information, and which host is acting as the mail hub of the system group or domain.

prerequisite

Before setting up domain name resolution, you need to prepare the domain name, website (or email). It includes:

1. Has a domain name.
2. The server space has been prepared and the website content has been uploaded to the server.
3. The website filing has been completed.
4. Obtain the host IP address (or email MX record) from the server provider, which needs to be used in resolution settings.

Domain name resolution process

Operation steps

Login, console ->domain name ->domain name management

Select the domain name for domain name resolution and click Manage Domain Name

Enter the domain name control panel

Fill in the server IP for domain name resolution

be careful:

It takes 0-72 hours to modify the DNS server globally. If you find that records in some places are not effective, and the time to modify DNS is less than 72 hours, please wait patiently