Should domain name resolution be broken

Time:2020-10-20

Original address: https://www.wjcms.net/archive…

preface

Domain name servers respond to DNS requests based on resource records. In DNS system, the most common resource record is Internet class record. Resource record is a 4-tuple containing the following fields: name, value, type and TTL. Where TTL is the lifetime of the record, which determines when the resource record should be removed from the cache; the values of name and value depend on the type, that is, the record type. Internet resource records can be divided into the following types: A / CNAME / TXT / NS / MX / SRV / CAA / explicit URL / implicit URL.

Add record step

  1. Click Add record
  2. Input the host record, which can be set by yourself, but there are rules. See the host record for details
  3. Enter host IP (web address)
  4. Click OK

Should domain name resolution be broken

Host record

Note: the host record (RR) value cannot start or end with “.”, “-“, and the host record (RR) value cannot have a continuous “.”. . the length of each split string cannot exceed 63 characters

Www means the domain name after resolution is www
Demo means that the domain name after resolution is demo. Domain name
Mail means that the domain name after resolution is mail. Domain name
@Indicates that the primary domain name is resolved directly
Represents universal resolution. domain name

Record type

Now we will analyze one by one, you can choose your own parsing type according to your needs.

A – point the domain name to an IPv4 address

A record:Address record is used to specify the IPv4 address of the domain name. If you need to point the domain name to an IP address, you need to add a record.
Reference standard:RR value can be null, that is, @ resolution; no underscores are allowed;
The specific analysis is as follows:
Should domain name resolution be broken

Note: the record value must be the value of IPv4, in IPv4 address format

CNAME – points a domain name to another domain name

CNAME record:If you need to point a domain name to another domain name and another domain name provides an IP address, you need to add a CNAME record.
Reference standard:In addition to letters, numbers, “-” (middle horizontal bar) and “\ (underscores); RR values are not allowed to be empty (i.e. @); underscores are allowed
Should domain name resolution be broken

Note: the record value here should be the domain name and not IP. When accessing the resolution record, it will point to the domain name of the record value.

For example: visit here baidu.wujiajz.com Will jump to visit www.baidu.com

Txt – text length limit is 512, usually do SPF record (anti spam)

Txt record:You can fill in anything here. The length limit is 255. Most of the txt records are used to do SPF records (anti spam). String; length less than 512, legal characters: upper and lower case letters, numbers, spaces, and the following characters: ~ =:; /. @ + ^*
Reference standard:In addition, the valid characters include letters, numbers, “-” (middle horizontal bar), and “\ (underline); RR value can be null, i.e. @ parsing; can contain underscores; does not support pan parsing
Should domain name resolution be broken

Note: in addition, setting SSL also requires setting the txt type resolution verification.

Should domain name resolution be broken

NS – specifies the subdomain name to another DNS server for resolution

NS record:Domain name server records, if you need to send the subdomain name to other DNS service providers for resolution, you need to add ns records.
Used to indicate which server resolves the domain name. When you register a domain name, there is always a default DNS server. Each registered domain name is resolved by a DNS domain name server. The DNS server ns record address usually appears in the following form:
We can see the default DNS server of your domain name, as shown in the figure below. If you want to change, you can add ns records.
Reference standard:RR value cannot be empty; underscores are allowed; pan resolution is not supported
Should domain name resolution be broken
dns1.domain.com
dns2.domain.com
Should domain name resolution be broken

Note:

(1) The smaller the number in priority, the higher the level;
(2) “IP address / host name” can be filled in with IP address or ns.mydomain.com Such a host address, but you must ensure that the host address is valid. For example, will news.mydomain.com The NS record points to ns.mydomain.com When setting ns records, you need to set ns.mydomain.com Otherwise, the NS record will not be parsed normally;
(3) NS record takes precedence over a record. That is, if both ns record and a record exist in one host address, the a record is not valid. The NS record here is only valid for subdomains.

AAAA – points the domain name to an IPv6 address

AAAA record:Same as a record, used to specify the IPv6 address (for example: ff06:0:0:0:0:0:0: C3) corresponding to the host name (or domain name).
Reference standard:RR value can be null, that is, @ resolution; no underscores are allowed;
Should domain name resolution be broken

Note: format IPv6 address format

SRV – records the servers that provide a specific service

SRV record:It records which computer provides which service. The format is: name, point and protocol type of the service
Reference standard:Is a name and can contain the underline “_ “And dot”. “; underscores are allowed; nulls are allowed (i.e. @); pan parsing is not supported
Format:SRV record format is: priority weight port destination address, each item should be separated by a space. For example, “0 5 5060 sipserver.example.com ”。
For example:
_docker-server._tcp.xxx.com. IN SRV 5 0 5269 docker-server.l.google.com.
Meaning of the project:
A kind of The name of the docker server service
A kind of The type of protocol used by TCP, such as_ TCP “or”_ udp”
ioio.name Name of SRV domain
5 – priority, similar to MX record
0 – weight
5269 – port
docker-server.l. google.com -The host name (target) of the actual service provided.
Should domain name resolution be broken

Note: priority: priority, a number between 0 and 65535; weight: weight, a number between 0 and 65535; port: the port number of the service provided, a number between 0 and 65535; target: the target address of the service, which is nametype and exists. reference resources: http://en.wikipedia.org/wiki/… http://www.rfc-editor.org/rfc/rfc2782.txt

MX – point mail to DNS address

MX records: if you need to set up a mailbox so that the mailbox can receive mail, you need to add MX records.
Should domain name resolution be broken

Caa-ca certification authority authorization verification

Reference standard:RR value can be null, that is, @ resolution; no underscores are allowed;
The format is: [flag] [tag] [value], which is composed of a flag byte [flag] and a tag [tag] – value [value] pair called an attribute. For example: @ 0 issue“ symantec.com “Or @ 0 iodef” mailto:[email protected]
Should domain name resolution be broken

Explicit URL – redirects the domain name to another address

Explicit URL: when redirecting from one address 301 to another, you need to add explicit URL records (Note: DNSPod only supports 301 redirection at present).
Format: URL address (case sensitive), with a maximum length of 500 characters, in which domain name, such as a.com, must be case insensitive; protocol: optional, such as HTTP, HTTPS, the default is HTTP port: optional, such as 81, the default is 80; path: optional, case sensitive, such as / path / to /, the default is /; file name: optional, case sensitive, such as file.php , default none; parameter : optional, case sensitive, such as? User = my*, none by default.
Should domain name resolution be broken

Implicit URL – similar to explicit URL, but hides the real target address

Implicit URL: similar to explicit URL, the difference is that the implicit URL does not change the domain name in the address bar.

Similar to explicit URL.

The difference between the two: explicit URL is more similar to jump, that is, a.com resolves to b.com, that is to say, when visiting a.com, he will jump to b.com, which is a direct jump. However, the actual address of a.com is still hidden, but the content is displayed.

Should domain name resolution be broken