Help Center> Domain Name Service> FAQs> Public Zones> Why Is a Message Indicating Conflict with an Existing Record Set Displayed When I Add a Record Set?
Updated on 2022-09-22 GMT+08:00

Why Is a Message Indicating Conflict with an Existing Record Set Displayed When I Add a Record Set?

If message "This record set is in conflict with an existing one" is displayed, the record set you are trying to add conflicts with or is the same as an existing record set.

Table 1 lists the rules.

Table 1 Restrictions between record types
  

NS

CNAME

A

AAAA

MX

TXT

PTR

SRV

CAA

NS

No limita

Conflict

No limit

No limit

No limit

No limit

No limit

No limit

No limit

CNAME

Conflictb

No limit

Conflict

Conflict

Conflict

Conflict

Conflict

Conflict

Conflict

A

No limit

Conflict

No limit

No limit

No limit

No limit

No limit

No limit

No limit

AAAA

No limit

Conflict

No limit

No limit

No limit

No limit

No limit

No limit

No limit

MX

No limit

Conflict

No limit

No limit

No limit

No limit

No limit

No limit

No limit

TXT

No limit

Conflict

No limit

No limit

No limit

No limit

No limit

No limit

No limit

PTR

No limit

Conflict

No limit

No limit

No limit

No limit

No limit

No limit

No limit

SRV

No limit

Conflict

No limit

No limit

No limit

No limit

No limit

No limit

No limit

CAA

No limit

Conflict

No limit

No limit

No limit

No limit

No limit

No limit

No limit

a: NS record sets cannot be configured for primary domains like example.com. There is no such restriction on subdomains (for example, www.example.com).

b: For primary domains like example.com, CNAME and NS record sets can coexist. For subdomains like www.example.com, CNAME record sets conflict with NS record sets.

The rules are as follows:

  • Conflict: The two types of record sets cannot have the same resolution line.
  • No limit: The two types of record sets can coexist.

In the standard DNS FRC protocol, CNAME has the highest priority. If CNAME and other types (such as MX) coexist, CNAME records may hijack MX resolution records.

For example, CNAME resolution has been added to the local DNS and cached. When the client adds MX resolution (using the mailbox to send emails), the local DNS preferentially returns the CNAME cache instead of requesting MX resolution from the Internet. As a result, the mailbox fails to send emails.

You are advised to configure email domain names and website domain names at the same time. For example, if the level-1 domain name xxx.com is used as an email address, you do not need to add CNAME resolution for xxx.com. Instead, you can directly add an A record to resolve the domain name to the IP address.

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