Understanding DS Records

Learn how DS records create a chain of trust between parent and child DNS zones

What is a DS Record?

A DS (Delegation Signer) record is a critical component of DNSSEC that creates a chain of trust between a parent and child zone. It contains a hash of a DNSKEY record from the child zone, allowing validation of the child zone's authenticity.

Format:

domain.com.    IN    DS    key-tag algorithm digest-type digest

Example:

# DS record using SHA-256
example.com.    IN    DS    12345 13 2 123456789ABCDEF...

# DS record using SHA-384
example.com.    IN    DS    54321 14 4 FEDCBA987654321...

Note: Digest values are truncated for readability. Actual digests are much longer.

Common Uses

Establishing DNSSEC chain of trust
Validating child zone's DNSKEY records
Securing zone delegations
Preventing zone spoofing attacks
Implementing secure domain transfers

Best Practices

✓
Use strong hash algorithms
Prefer SHA-256 (algorithm 2) or SHA-384 (algorithm 4) for digest creation.
✓
Coordinate with parent zone
Ensure proper communication with parent zone operators when updating DS records.
✓
Regular verification
Regularly verify DS records match current DNSKEY records and validate DNSSEC chain.

Common Pitfalls

⚠️
Mismatched records
DS records not matching current DNSKEY records can break the DNSSEC chain of trust.
⚠️
Poor timing in updates
Incorrect timing when updating DS records can cause validation failures.
⚠️
Weak algorithms
Using deprecated hash algorithms reduces security and may cause compatibility issues.

Advanced Tips

Key Rollover Process

When performing DNSKEY rollovers, carefully coordinate DS record updates with the parent zone to maintain an unbroken chain of trust.

Multiple DS Records

Consider publishing multiple DS records with different algorithms to provide algorithm diversity and improve security.

Automation Considerations

Implement automated monitoring and validation of DS records to quickly detect and respond to any issues in the trust chain.

Security Considerations

🔒
Trust Chain Integrity
Regularly validate the entire DNSSEC trust chain to ensure DS records are properly securing the delegation.
🔒
Algorithm Selection
Use cryptographically strong hash algorithms and maintain awareness of algorithm deprecation.
🔒
Emergency Procedures
Maintain emergency procedures for rapid DS record updates in case of security incidents.

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