One of your team members has asked you to analyze the following SOA record. What is the TTL? Rutgers.edu.SOA NS1.Rutgers.edu ipad.college.edu (200302028 3600 3600 604800 2400.)

Question

Options

• A200303028
• B3600
• C604800
• D2400
• E60
• F4800

• B
  6% (1)
• D
  94% (16)

Explanation

SOA Record TTL Explanation

Option D (2400) is correct because in a SOA (Start of Authority) record, the fields appear in a specific order: Serial, Refresh, Retry, Expire, and Minimum TTL (negative caching TTL). The five numbers (200302028 3600 3600 604800 2400) map to these fields respectively, making 2400 the Minimum/Negative Caching TTL - which is what the question is asking for.

• A (200303028) is wrong because that is the serial number, used for zone versioning/transfers
• B (3600 - first occurrence) is the Refresh interval, telling secondary servers how often to check for updates
• C (604800) is the Expire value, indicating how long a secondary server can serve zone data without contact
• B (3600 - second occurrence) is the Retry interval, indicating how long to wait before retrying a failed refresh

Memory Tip: Use the acronym "Serial Refreshes, Retries Expire Minimally" → S-R-R-E-M to remember the SOA field order. The last value is always the Minimum TTL, so count to the final number in the parentheses when answering TTL questions.

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