# Record Set Types and Configuration Rules

#### Type

Table 1 describes the record set types.

Table 1 Record set types
Record Set Type | Scenario | Description
--- | --- | ---
A | Public and private zones | Maps domains to IPv4 addresses.
CNAME | Public and private zones | Maps one domain name to another or multiple domain names to one domain name.
MX | Public and private zones | Maps domain names to email servers.
AAAA | Public and private zones | Maps domain names to IPv6 addresses.

TXT

Public and private zones

Specifies text records. It is usually used in the following scenarios:

- To record DKIM public keys to prevent email fraud.
- To record the identity of domain name owners to facilitate domain name retrieval.

SRV | Public and private zones | Records servers providing specific services.

NS

Public and private zones

Delegates subdomains to other name servers.

- For public zones, an NS record set is automatically created, and you can add NS record sets for subdomains.
- For private zones, an NS record set is automatically created, and you cannot add other NS record sets.

SOA | Public and private zones | Specifies the master authoritative DNS server for a domain name. The SOA record set is created by the system and cannot be added manually.
CAA | Public zone | Grants certificate issuing permissions to CAs. CAA record sets can be used to prevent the issuance of unauthorized HTTPS certificates.
PTR | Private zone | Maps IP addresses to domain names.

#### Record Set Configuration

Table 2 lists the value requirements for different types of record sets.

Table 2 Requirements for record set values
Record Set Type | Value | Example
--- | --- | ---
A | IPv4 addresses mapped to the domain name You can enter a maximum of 50 record values, each on a separate line. | 192.168.12.2 192.168.12.3
CNAME | Domain name alias. You can enter only one domain name. | www.example.com

MX

Email server address

You can enter a maximum of 50 record values, each on a separate line.

The format is [priority][mail server host name].

Configuration rules:

- priority: priority for an email server to receive emails. A smaller value indicates a higher priority.
- mail server host name: domain name provided by the email service provider

10 mailserver.example.com.

20 mailserver2.example.com.

AAAA | IPv6 addresses mapped to the domain name You can enter a maximum of 50 record values, each on a separate line. | ff03:0db8:85a3:0:0:8a2e:0370:7334

TXT

Text content

Configuration rules:

- Text record values must be enclosed in double quotation marks.
- One or more text record values are supported, each on a separate line.

  A maximum of 50 text record values can be entered.

- A single text record value can contain multiple character strings, each of which is double quoted and separated from others using a space.

  One character string cannot exceed 255 characters.

  A value must not exceed 4096 characters.

- The value cannot be left blank.
- The text cannot contain a backslash (\).

- Single text record:

  "aaa"

- Multiple text records:

  "bbb"

  "ccc"

- A text record that contains multiple strings:

  "ddd" "eee" "fff"

SRV

Server address

You can enter a maximum of 50 record values, each on a separate line.

The value format is [priority] [weight] [port number] [server address].

Configuration rules:

- The priority, weight, and port number range from 0 to 65535.
- A smaller priority value indicates a higher priority.
- A larger weight value indicates a larger weight.
- The server address is the domain name of the target server.

  Ensure that the domain name can be resolved.

NOTE:

The system checks the priority values first. If the priority values are the same, the system will check the weight values.

2 1 2355 example_server.test.com

NS | DNS server address You can enter a maximum of 50 record values, each on a separate line. | ns1.example.net ns2.example.net

CAA

CA to be authorized to issue certificates for a domain name or its subdomains

You can enter a maximum of 50 record values, each on a separate line.

The format is [flag] [tag] [value].

Configuration rules:

- flag: certificate authority (CA) identifier, which is an unsigned character ranging from 0 to 255. Usually, the value is set to 0.
- tag: a string of 1 to 15 characters composed of letters and digits from 0 to 9. The tag can be one of the following:
  - issue: authorizes CAs to issue all types of certificates.
  - issuewild: authorizes CAs to issue wildcard certificates.
  - iodef: requests notifications once CAs receive invalid certificate requests.
- value: authorized CA or email address/URL required for notification once the CA receives invalid certificate requests, depending on the value of tag. The value must be enclosed in quotation marks (""). It is a string of 1 to 255 characters, including letters, digits, spaces, and special characters -#*?&_~=:;.@+^/!%

0 issue "ca.abc.com"

0 issuewild "ca.def.com"

0 iodef "mailto:admin@domain.com"

0 iodef "http:// domain.com/log/"

PTR | Private domain name mapped to the private IP address. You can enter only one domain name. | www.example.com.

Parent topic: Record Set