Intel 7190 manual Authoritative DNS Servers, Multi-Site Load Balancing

C H A P T E R 2 Traditional DNS

7140/7170

(Los Angeles)

Client

(San Diego)

7190

7140/7170

(Chicago)

ns.mstd-ex.com (Chicago) Authority for msd-ex.com

Local DNS server

(San Diego)

Multi-Site Load Balancing

Authoritative DNS Servers

The DNS maps, or “resolves” hostnames into IP addresses. It is, in effect, a distributed database operating through a distributed, hierarchical system of Domain Name Servers. Thus, if the local DNS server cannot resolve a name, it looks “upstream” to consult a Root Domain Server for help. The Root Domain Server in turn asks the Authoritative Name Server (i.e., the owner of the name it is trying to resolve) to return the appropriate IP address for the requested name.

To illustrate

1.The client sends a query to its configured DNS (all clients are configured with the address of their DNS server) to resolve a par- ticular domain name (e.g., www.mstd-ex.com).

2.The client DNS server sends a query to the Root Domain server for the .com domain (every DNS server is configured with the root server information) to resolve mstd-ex.com.

3.The Root Domain server responds with the address of the Authoritative DNS server for the mstd-ex.comdomain.

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