DNS_ERROR_DNAME_COLLISION - 9721 (0x25F9)
A DNAME record already exists for given name.
Updated: Feb 21, 2026
Technical Background
The DNS_ERROR_DNAME_COLLISION error is a specific error code that indicates an attempt to create or modify a DNAME record in the Domain Name System (DNS) where a DNAME record already exists for the given name. This error is relevant within the context of DNS management and resolution mechanisms.
Error Details
The DNS_ERROR_DNAME_COLLISION error is returned when an operation intended to add or update a DNAME record encounters a conflict because another DNAME record with the same target name already exists in the DNS database. A DNAME record is used for mapping a domain name to a set of domain names, effectively creating aliases.
Common Causes
- Duplicate DNAME Record: Attempting to add or update a DNAME record that already has an existing entry with the same target name.
- Incorrect Object Type: The operation was intended for a different type of DNS record (e.g., A, CNAME) instead of a DNAME record.
Real-World Context
This error typically occurs during administrative tasks involving DNS management, such as adding or modifying domain mappings. It is important to ensure that the target name specified in the operation does not already exist as a DNAME record before performing the operation.
Is This Error Critical?
The DNS_ERROR_DNAME_COLLISION error is generally not critical for system stability but can prevent intended operations from completing successfully. Administrators should address this issue by either removing or updating the existing conflicting DNAME record, or by ensuring that the target name specified in the operation does not already exist.
How to Diagnose
To diagnose and resolve DNS_ERROR_DNAME_COLLISION, follow these steps:
- Review Operation Context: Verify the specific operation being performed (addition or modification) and ensure it is intended for a DNAME record.
- Validate Parameters: Confirm that the target name specified in the operation does not already exist as a DNAME record.
- Confirm Object Types: Ensure that the operation context aligns with the expected DNS record type (DNAME).
- Verify Input Data: Check for any potential data corruption or incorrect input values that might lead to this error.
How to Resolve
To resolve DNS_ERROR_DNAME_COLLISION, take one of the following actions:
- Correct Parameter Usage: Ensure that the target name specified in the operation does not already exist as a DNAME record. If it does, either remove or update the existing entry before performing the intended operation.
- Adjust Operation Context: Verify and adjust the context to ensure that the operation is correctly targeting a DNAME record.
Developer Notes
Developers should be aware of this error when implementing DNS management functionalities in their applications. Proper validation of input parameters and target names can help prevent this error from occurring.
Related Errors
DNS_ERROR_NAME_NOT_RESOLVEDDNS_ERROR_NO_SUCH_DOMAINDNS_ERROR_RCODE_REFUSED
FAQ
Q: What does the DNS_ERROR_DNAME_COLLISION error indicate?
A: It indicates that a DNAME record already exists for the given name, preventing the intended operation from completing.
Q: How can I prevent this error from occurring?
A: Ensure that the target name specified in your operations does not already exist as a DNAME record. Validate input parameters and object types before performing DNS management tasks.
Summary
The DNS_ERROR_DNAME_COLLISION error is specific to situations where an attempt is made to create or modify a DNAME record, but a conflicting entry already exists. Administrators should address this by either removing or updating the existing DNAME record or ensuring that the target name specified in their operations does not already exist.