Navigate to Policy | Rules and Policies> DNS Rules page to configure DNS Proxy. For more information about DNS Rules, refer to Rules and Policies guide.
From the Adding DNS Policy option, to use UDP only or UDP and TCP. Choose the following Service from the Source/Service tab:
DNS (Name Service)
DNS (Name Service) TCP
DNS (Name Service) UDP
For DNS over UDP requests only, select Enforce DNS Proxy for All DNS Requests. This option is not selected by default
For DNS over UDP requests only, select Enable DNS Proxy Cache. This option is not selected by default.