A Secondary IP Set is a set of one or more master name server IP addresses for a secondary DNS domain. A secondary DNS domain must have an IP Set applied to it at all times. You can modify or switch IP Sets if required. If the IP Set you want to use is not available, create a new one.
Step 1: Select Secondary DNS
Step 2: Select the domain
Step 3: Click on the “IP Set” drop-down menu to select another IP Set.