Ali and so resolve DNS concepts depth analysis

Summary

The design concept of this paper are:
- Host wwwRecord: @, ,***
- Record A记录Type: CNAME记录, ,TXT记录
- Parsing route
- isp: Internet Service Provider
- Record values
- TTL: time to liveCache lifetime
- 地方DNS
- DNSPod
Scene Description

DNS has a " 记录数" and 解析设置" ."

Enter 解析设置:

Detailed knowledge can refer to the upper right corner of the " 如何设置解析." Here only to make a page parameter to understand.

Domain names 12345.com, for example
Host Record

Host Record, That is 域名前缀, common are:

the WWW : the domain name resolves to www.12345.com;

@ : Direct resolve the main domain name 87677677.com
***: Pan-resolution, matching all other domain names*.87677677.com
Record Type

To point to the host service provider IP address, select the type A ; to point a domain name, select the type of CNAME .
A recording: the recording address, the domain name for specifying IPv4 address (for example 8.8.8.8), if the domain name to point to a required IP address (external address), you need to add the A record.
CNAME record: If you need to point the domain name to another domain name, then the domain name provided by another IP address, you need to add a CNAME record.

TXT record: If you want to identify the domain name and description, you can use TXT record, the vast majority of TXT record is used to make SPF record (anti-spam).
Parse line (isp)

isp(Internet Service Provider)¹ : Internet service provider, referring to the public for the following information services operators:

First, access to services that help users access Internet;

Second navigation services that help users find the information they need on the Internet;

Third, information services, namely the establishment of a data service system, the collection, processing and storage of information, regular maintenance updates, content and providing information services to users over the network.

Let the user specify line access to this IP, the common usage is as follows:
- ** default: ** must be added, or only individual designated route to visit your site. If the double resolution, recommended [default] [fill line telecommunications IP].
- ** Unicom: Unicom users [**] individually specify the server IP, other users can still access the [default].
- ** Search Engine: ** specify a server IP lets crawl.
Record values

It is the domain name ( 12345.com) in the12345

The most common is to provide a space 【IP 地址】to fill in here, fill in the value of each type of record is as follows:
- ** A record: * Enter your server IP, if you do not know, ask your hosting provider.
- ** CNAME record: ** Fill in the domain name space providers to provide you with. For example 2.com.
- ** TXT record: ** Record value and there is no fixed format, but in most cases, TXT records are used to make anti-spam SPF. The most typical SPF TXT record format examples " v=spf1 a mx ~all" indicates the IP address of the domain name only A record and MX records have permission to use the domain name to send mail.
TTL²

TTL：即 Time To Live，Cache life time. Refers to 地方 DNScache your domain name record time information, the cache will fail again to DNSPodget the recorded value. Our default of 600 seconds is the most commonly used, without modification.
- 600 (10 minutes): 600 normally recommended.
- 60 (1 minute): If you frequently modify IP, modify the record one minute to take effect. 60 long-term use, parsing speed will be slightly affected.
- 3600 (1 hour): If your IP rarely changes (several times a year), it is recommended to select 3600, fast parsing speed. If you want to modify IP, one day in advance to 60, it can quickly take effect.
Local DNS and DNSPod

Two concepts mentioned here: 地方DNSand DNSPod.

DNSPot( Official website ), to provide one-stop service domain, including 域名注册, DNS 管理, SSL 证书, 网站备案and so on.

DNSPodEstablished in March 2006, it is a free smart DNSproducts. DNSPodIt may also have Telecom, China Unicom, education network server site offers intelligent resolution.

地方DNS( List View )
References