The DNS Resolver Service (DRS) is a proprietary DNS resolver that is responsible for handling all DNS queries from clients. DRS instances, when deployed, are associated with an Edge Site, which will determine the configuration applied to DRS. DRS is not configured directly, but rather is configured through other objects such as Policies, Namespaces, and Domain Lists. Best practices for these items can be found below.
BEST PRACTICE: Service upgrades happen at the site level, meaning that all DRS instances associated with a site will be upgraded in series. In the unlikely event of an issue with a new DRS version this may lead to an entire site being unavailable for resolution. To mitigate this risk it is recommended to associate local DRS instances with two or more different sites. For example, if two service points reside in the same data center, associate one with “Data Center - A” and one with “Data Center - B.” That way, the administrator can upgrade “Data Center - A,” test functionality/stability, and then upgrade “Data Center - B” when comfortable.