Add Exernal Secondary DNS server to Grid Primary

[#1]

Currently I am using one of Grid members as Grid Primary DNS. If I added Exernal Secondary DNS server to the Grid, do I need in this case to add the IP address of the new Exernal DNS server in the allowed zone transfare list. or it will be allowed without any aditional actions.

[#2]

Adding the external secondary server in the NS group or the members section of a zone automatically adds itself to config file under both allow-transfer and also-notify