- Inside a rule, choose the Cache tab
- Enable DNS Caching activate the cache for responses that matches the rule.
¶ Max Records in memory
It Is the maximum number of entries stored in the cache.
For performance reasons the cache will pre-allocate buckets based on the maximum number of entries, so be careful to set the first parameter to a reasonable value.
Something along the lines of a dozen bytes per pre-allocated entry can be expected on 64-bit.
That does not mean that the memory is completely allocated up-front, the final memory usage depending mostly on the size of cached responses and therefore varying during the cache’s lifetime.
Assuming an average response size of 512 bytes, a cache size of 10000000 entries on a 64-bit host with 8GB of dedicated RAM would be a safe choice.
Default value of 10 000 entries handle 5MB of memory.
- Cache TTL (Max): Is the maximum lifetime of an entry in the cache
- Cache TTL (Min): Is the minimum lifetime an entry should have to be considered for insertion in the cache.
- Negative Cache TTL: Is the lifetime that will be used when a stale cache entry, Server Failure or a Refused response are returned.