Knowledge

DNS_ERROR_ALIAS_LOOP - 9722 (0x25FA)

An alias loop has been detected with either CNAME or DNAME records.

Updated: Feb 21, 2026

Technical Background

The DNS_ERROR_ALIAS_LOOP error code, with the numeric value of 9722 and the hexadecimal representation 0x25FA, indicates that a loop has been detected during the resolution process involving CNAME or DNAME records. This error is specific to DNS (Domain Name System) operations within Windows environments.

Error Details

This error typically arises when a domain name system query results in an infinite loop due to circular references between CNAME (Canonical Name) and DNAME (Delegated Name) records. A CNAME record maps one fully qualified domain name to another, while a DNAME record maps a prefix of a domain name to another domain name.

Common Causes

  • Circular References: The most common cause is the presence of circular references in the DNS configuration. For example, if example.com points to alias.example.com, and alias.example.com points back to example.com, this would result in an alias loop.
  • Misconfigured DNS Records: Incorrectly configured CNAME or DNAME records can lead to such loops.

Real-World Context

In practical scenarios, this error might occur when a network administrator has inadvertently set up a DNS configuration that creates a circular reference. This can happen during the process of setting up domain aliases or delegations without proper validation and testing.

Is This Error Critical?

The presence of an alias loop can significantly impact the performance and reliability of DNS resolution processes. It may lead to delays in name resolution, increased network traffic due to repeated queries, and potential denial-of-service conditions for affected domains.

How to Diagnose

To diagnose this issue, follow these steps:

  1. Review DNS Configuration: Check the DNS records for any circular references or misconfigurations.
  2. Validate Parameters: Ensure that all CNAME and DNAME records are correctly pointing to valid domain names without creating loops.
  3. Confirm Object Types: Verify that each record is of the correct type (CNAME or DNAME) and does not inadvertently create a loop.

How to Resolve

To resolve this issue, take the following actions:

  1. Correct Parameter Usage: Ensure all CNAME and DNAME records are correctly configured without creating circular references.
  2. Adjust Operation Context: If necessary, adjust the context in which DNS resolution is performed to avoid triggering the loop.
  3. Restore Data: In some cases, restoring or reconfiguring the affected DNS records may be required.

Developer Notes

When developing applications that rely on DNS resolution, it is crucial to validate and test DNS configurations thoroughly to prevent alias loops from occurring. This can help ensure reliable and efficient name resolution in networked environments.

Related Errors

  • DNS_ERROR_NAME_NOT_RESOLVED: Indicates a failure to resolve the domain name.
  • DNS_ERROR_NO_SUCH_HOST: Occurs when the host does not exist or is unreachable.

FAQ

Q: What causes DNS_ERROR_ALIAS_LOOP?

A: This error typically occurs due to circular references in CNAME and DNAME records, leading to an alias loop during resolution.

Q: How can I prevent this error from occurring?

A: Ensure that all DNS records are correctly configured without creating any circular references. Regularly validate and test your DNS configurations.

Summary

The DNS_ERROR_ALIAS_LOOP error code is a specific indication of an alias loop in the DNS resolution process involving CNAME or DNAME records. It highlights the importance of proper configuration and validation to maintain reliable network operations.