Functions

Table 1 lists basic functions of the DNS service.

Before you use the DNS service, you'd better get familiar with Product Concepts to better understand the functions.

**Table 1** Common DNS functions
Category	Function	Description
Public domain resolution	Public zone	A public zone is used to host a domain name you want to make accessible over the Internet and contains information about how you want to route traffic for the domain name and all its subdomains. You can create, modify, delete, enable, disable, and view public zones. For details, see Public Zone.
	Domain name level	You can create public zones for second-level domain names and their subdomains. For domain names with 1-level suffixes like .com, you can create zones for example.com and www.example.com. For domain names with 2-level suffixes like .com.cn, you can create zones for example.com.cn and www.example.com.cn.
	Record set	A record set is a collection of resource records that belong to the same domain name. A record set defines the resolution type and value of a domain name. You can add, modify, delete, view, disable, or enable record sets of the A, CNAME, MX, AAAA, TXT, SRV, NS, and CAA types for public zones. For details, see Record Set.
	Reclaiming a public zone	If a public zone has been created for your domain name by another user, you can reclaim the public zone by proving that you are the holder of the domain name. For details, see Reclaiming a Public Zone.
	Wildcard DNS record set	You can add record sets for all subdomains of a second-level domain name. For details, see Creating a Wildcard DNS Record Set.
	TTL	TTL is short for time to live, which specifies the cache period of resource records on a local DNS server, in seconds. The TTL value ranges from 1 to 2147483647.
	Weight	Weight indicates the proportion of DNS queries that will be routed to the record set. If a resolution line in a zone contains multiple record sets of the same type, you can set different weights to each record set. For details, see Configuring Weighted Routing.
	Batch operation	You can delete multiple public zones at a time.
Private domain name resolution	Private zone	A private zone is used to host private domain names that are used in VPCs. You can create, modify, delete, and view private zones, associate private zones with VPCs, and disassociate private zones from VPCs. Private zones can be created without the need to register domain names. Each private zone must be unique in the associated VPC. For details, see Private Zone.
	Associating a private zone with or disassociating a private zone from a VPC	You can associate a private zone with a VPC or disassociate a private zone from a VPC. For details, see Associating a VPC with a Private Zone and Disassociating a VPC from a Private Zone.
	Record set	A record set is a collection of resource records that belong to the same domain name. A record set defines the resolution type and value of a domain name. You can add, modify, delete, or view A, CNAME, MX, AAAA, TXT, PTR, and SRV record sets for private zones. For details, see Record Set.
	Wildcard DNS record set	You can add record sets for all subdomains of a private domain name. DNS provides resolution services for all subdomains. For details, see Creating a Wildcard DNS Record Set.
	TTL	TTL is short for time to live, which specifies the cache period of resource records on a local DNS server, in seconds. The TTL value ranges from 1 to 2147483647.
	Batch deletion	You can delete multiple private zones at a time.
Reverse resolution	PTR record	Reverse resolution involves obtaining a domain name based on an IP address. This function is useful when you want to build an email server. You can create, modify, and delete PTR records. For details, see PTR Record.
Reverse resolution	TTL	TTL is short for time to live, which specifies the cache period of resource records on a local DNS server, in seconds. The TTL value ranges from 1 to 2147483647.
Intelligent resolution	ISP line	DNS can return the optimal IP addresses to end users based on the carrier networks they use. For details, see Configuring ISP Lines.
Intelligent resolution	Region line	DNS can return the optimal IP addresses to end users based on their geographic locations. For details, see Configuring Region Lines.
Record set	Global search of record sets	DNS allows you to centrally manage record sets in both public and private zones. You can: Search for record sets by status, type, name, value, ID, or tag. Modify, delete, disable, or enable record sets in public zones. Modify or delete record sets in private zones. For details, see Searching for Record Sets.
Record set	Batch operations	You can import, export, and delete record sets of both public and private zones in batches. For details, see Importing Record Sets and Exporting Record Sets.
Audit	Audit logs	With CTS, you can record operations associated with DNS for later query, audit, and backtrack operations. Huawei Cloud allows you to view audit logs. You can view and export operation records of the last seven days on the CTS console.
Tag	Resource tagging	You can configure tags for public zones, private zones, record sets, and PTR records. You can also use predefined tags of TMS to quickly associate tags with resources.
Quota	Quota adjustment	Quotas are enforced for service resources on the platform to prevent unforeseen spikes in resource usage. Quotas can limit the number and capacity of resources available to end users, for example, how many public zones, private zones, record sets, and PTR records you can create. If existing resource quotas cannot meet your service requirements, you can request higher quotas. For details, see Quota Adjustment.