Which DNS enumeration technique queries the DNS server for a specific cached DNS record?

Which DNS enumeration technique queries the DNS server for a specific cached DNS record?

• A. DNS Cache Snooping
• B. DNSSEC Zone Walking
• C. LDNS
• D. IPsec

Answer: (A)

DNS cache snooping focuses on finding out whether a specific DNS record is already stored in a target DNS server’s cache. The tester asks the server for that domain and watches how it responds. If the response comes back quickly and appears to be served from cache (often indicated by a shorter lookup time and TTL behavior), you can infer that the server has recently cached that record. This directly matches the idea of querying for a cached entry to see if it exists in the server’s memory. The other options don’t fit this goal. DNSSEC zone walking is about attempting to retrieve or infer entire zone data using DNSSEC-related methods, not about checking cached entries. LDNS is simply a DNS lookup library, not a specific enumeration technique. IPsec is a security protocol for securing IP communications and has no role in discovering cached DNS records.

DNS cache snooping focuses on finding out whether a specific DNS record is already stored in a target DNS server’s cache. The tester asks the server for that domain and watches how it responds. If the response comes back quickly and appears to be served from cache (often indicated by a shorter lookup time and TTL behavior), you can infer that the server has recently cached that record. This directly matches the idea of querying for a cached entry to see if it exists in the server’s memory.

The other options don’t fit this goal. DNSSEC zone walking is about attempting to retrieve or infer entire zone data using DNSSEC-related methods, not about checking cached entries. LDNS is simply a DNS lookup library, not a specific enumeration technique. IPsec is a security protocol for securing IP communications and has no role in discovering cached DNS records.