This read-write integer is an action trigger for flushing DNS cache contents: staticOnly clears manually configured hostname-to-IP mappings, dynamicOnly clears both negative and positive cache entries learned dynamically via DNS, and all clears every entry in both static and dynamic caches. An administrator uses this to force fresh DNS resolution after a known upstream record change, without waiting for TTLs to naturally expire. For example, after updating a server's IP address in DNS, an admin sets this OID to dynamicOnly to purge the stale cached mapping and force an immediate re-lookup.