(i) Recursive DNS queries :
web browser → recursive server,
(ii) Iterative DNS queries :
Query send to one after one server to find the Assigned IP of Domain
After recursive (no cached) then it send request to Root Name Server, TLD and Authoritative Nameserver, `
(iii) Non Recursive queries :
After recursive (if cached Query , then it return IP) , no more to next level of servers. Simply return error statement to browser