MACROMEDIA COLDFUSION 4.5-ADMINISTRING COLDFUSION..., Manual

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Chapter 6: Creating Scalable and Highly Available Web Sites 165
resolve the name-to-IP mapping before the browser can send a request to the
appropriate Web server.
To summarize, primary and local DNS servers work together to resolve name-to-IP
address mappings in the following way.
1. A user enters a Web site URL in his or her browser and presses Enter.
2. The browser checks the local DNS server for the name-to-IP address mapping.
The local DNS server typically resides at the facility where the Web servers are
hosted.
3. If the local DNS server does not have the mapping, it goes out to the Internet and
locates the primary DNS server to look up the name-to-IP address mapping.
If round-robin DNS is being used, the primary DNS server determines which
server in the cluster is next in line to receive the request.
4. The primary DNS server sends back the translation to the local DNS server, which
in turn sends it to the user’s browser.
5. The browser is now able to send an HTTP request to the correct Web server
hosting the site.
The following diagram illustrates this process.