Chapter 9 DNS Cache

9.1 Overview

The DNS SLB mechanism used by FortiBalancer appliance supports DNS cache feature. Upon receiving any type “A” or “AAAA” DNS responses, which are mapping of host names to IP addresses, FortiBalancer will save them in SLB DNS cache. Then, when the FortiBalancer appliance receives any DNS requests for the cached “A” or “AAAA” records from clients, the appliance will directly send back the “A” or “AAAA” responses to the clients. If there is no records in cache that hit the requests, the FortiBalancer appliance will communicate with the remote DNS server(s) directly, and then save the server responses in cache for responding to the coming requests.