What is the primary effect of enabling dynamic proximity measurement in GSLB when a DNS probe occurs?

• A. RTT is ignored in favor of TTL
• B. Proximity ranking uses only the first DNS response
• C. RTT is used to rank services after DNS resolution
• D. MIR is always preferred over RTT

Answer: (C)

Dynamic proximity measurement in GSLB uses real-time RTT data to decide where to direct a client. When a DNS probe runs, the system checks the latency to each potential service location. After DNS resolution, it ranks the available endpoints by those RTT measurements and returns the IP for the lowest-latency option. This ensures the client is steered toward the fastest reachable site based on current network conditions, rather than relying solely on static factors like TTL or on the first response seen. The other ideas don’t fit because RTT isn’t ignored; proximity isn’t limited to the first DNS reply; and there isn’t an absolute rule that MIR always supersedes RTT in this context.