SOA Serial Analyzer

Analyze Start of Authority (SOA) records to interpret serial number formats and examine DNS zone timing parameters. SOA records contain critical zone metadata including serial numbers for change tracking and timing values for zone transfers.

Domain Examples

SOA Analysis Configuration

About SOA Records and Serial Numbers

What is a SOA Record?

Start of Authority records contain administrative information about a DNS zone, including the primary server, contact email, and timing parameters that control zone transfers and caching behavior.

Serial Number Formats

  • YYYYMMDDNN: Date-based format (e.g., 2024031501 = March 15, 2024, revision 01)
  • Unix Timestamp: Seconds since epoch (e.g., 1710518400)
  • Sequential: Simple incrementing numbers (e.g., 1, 2, 3...)

Timing Parameters

  • Refresh: How often secondaries check for updates
  • Retry: Retry interval after failed transfers
  • Expire: When to stop serving if updates fail
  • Minimum: TTL for negative (NXDOMAIN) responses

Best Practices

  • Use YYYYMMDDNN format for predictable versioning
  • Set refresh to 3600-7200s for most zones
  • Retry should be shorter than refresh (1800-3600s)
  • Expire should be much longer (604800-1209600s)