DNS RR Types
The DNS resolver (DNS client) sends a query message to the DNS recursor (DNS recursive resolver) asking for the address of www.cisco.com.
The DNS recursor sends a query message to the root name servers looking for the .com domain name space.
The root name servers send a DNS referral response message to the DNS recursor informing it to ask the generic Top-Level Domain (gTLD) name servers for the .com domain name space.
The DNS recursor sends a query message to the gTLD name servers looking for the .cisco.com domain name space.
The gTLD name servers send a DNS referral response message to the DNS recursor informing it to ask the .cisco.com name servers, ns1.cisco.com or ns2.cisco.com, about this domain name space.
The DNS recursor sends a query to ns1.cisco.com or ns2.cisco.com, asking for www.cisco.com.
The .cisco.com name servers, ns1.cisco.com or ns2.cisco.com, send an authoritative DNS query response message to the DNS recursor with the A (address) RR information for www.cisco.com.
The DNS recursor sends a DNS query response message to the DNS resolver with the A (address) RR information for www.cisco.com.