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
Record Set Type	NS	CNAME	A	AAAA	MX	TXT	PTR	SRV	CAA
NS	No limit^a	Conflict	No limit	No limit	No limit	No limit	No limit	No limit	No limit
CNAME	Conflict^b	Duplicate	Conflict	Conflict	No limit	No limit	Conflict	Conflict	Conflict
A	No limit	Conflict	Duplicate	No limit	No limit	No limit	No limit	No limit	No limit
AAAA	No limit	Conflict	No limit	Duplicate	No limit	No limit	No limit	No limit	No limit
MX	No limit	No limit	No limit	No limit	Duplicate	No limit	No limit	No limit	No limit
TXT	No limit	No limit	No limit	No limit	No limit	Duplicate	No limit	No limit	No limit
PTR	No limit	Conflict	No limit	No limit	No limit	No limit	Duplicate	No limit	No limit
SRV	No limit	Conflict	No limit	No limit	No limit	No limit	No limit	Duplicate	No limit
CAA	No limit	Conflict	No limit	No limit	No limit	No limit	No limit	No limit	Duplicate
Conflict: The two types of record sets cannot coexist for the same name and line. No limit: The two types of record sets can coexist. WARNING: If the name is @ or empty, CNAME can coexist with MX or TXT of the same line. However, this may cause service risks, such as email-receiving or domain name verification failures. Duplicate: The record set cannot be the same as an existing one. a: NS record sets cannot be added for primary domains, but this restriction does not apply to subdomains. b: For primary domains, CNAME and NS record sets can coexist. For subdomains, however, CNAME record sets conflict with NS record sets and cannot be used together.

If the message is displayed, perform the following operations:

Delete the existing record set that conflicts with the record set that you want to add, and then add the record set.

Deleting a record set may cause domain name resolution to fail.
Set a different name for the record set.
Select a different line type.

The following examples describe how to solve common record set conflicts.

Conflicts When Adding an NS Record Set

You have hosted domain name example.com on the DNS service. An NS record set and an SOA record set are automatically created for the hosted zone and cannot be deleted.

If the resolution line is the same, you cannot add another NS record set for the domain name example.com.

In this case, use either of the following methods to add a record set:

Method 1: Add an NS record set for a subdomain of example.com.
In the following figure, an NS record set is added for 123.example.com, and the value of the record set is ns.example.com.

Figure 1 Adding an NS record set
Method 2: Add an NS record set for example.com, with a resolution line other than the default line.
In the following figure, an NS record set with the line type set to ISP is added for example.com, and the value of the record set is ns.example.com.

Figure 2 Adding an NS record set with an ISP line
Method 3: Change the value of the NS record set added to example.com.
To configure a new DNS server address for a domain name, modify the value of the NS record set added to the hosted zone. For more information, see What Are Huawei CloudDNS Server Addresses?

Special Handling of CNAME Record Set Conflicts

According to RFC 1034 and RFC 2181, CNAME has the highest priority. If a CNAME record set coexists with another type of record set of the same name and line, it overrides another type of the record set, which can cause service failures (for example, email-receiving or domain name verification failures).

When the name is @ or empty, Huawei Cloud DNS applies optimized conflict-handling rules for certain record set types. It also provides risk warnings to maintain standard compliance while allowing flexible service deployment.

If the name is @ or empty, CNAME can coexist with MX or TXT of the same line. However, this may cause service risks.

In email resolution scenarios, you can avoid service risks by adding CNAME record sets with different names for a domain name. For details, see Table 2.

**Table 2** Email domain record sets
Record Set Type	Name	Value	Description
MX	-	5 mx01.mailserver.com 10 mx02.mailserver.com	Email server address, which is obtained from the email service provider
TXT	-	"v=spf1 include:spf.mailserver.com -all"	SPF records used to prevent spam
CNAME	mail	mailserver.com	Use domain name mail.example.com to log in to the mailbox.
CNAME	smtp	smtp.mailserver.com	Use smtp.example.com as the alias of smtp.mailserver.com.
CNAME	imap	imap.mailserver.com	Use imap.example.com as the alias of imap.mailserver.com.
CNAME	pop	pop.mailserver.com	Use pop.example.com as the alias of pop.mailserver.com.

Parent Topic: Public Zones

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