RA is a Word property that indicates if recursive query support is available on the DNS server responding to the DNS query. RA will contain the value 1 when recursive queries are availabale on the name server, or the value 0 when recursive queries are not supported or allowed for the DNS resolver. 

Use RD to indicate if recursive query support is desired in a DNS request. 

RA is represented in a DNS header as a bit field. Changing the value of RA ensures that the appropriate bit field is updated in the DNS header for the message packet.