Configure DNS polling for a Windows environment (Simple load Balancing)

Objective:

What is DNS polling?

A domain name for multiple IP A records resolution, the DNS server will resolve the request in the order of a records, one by one assigned to a different IP, so that the simple load balancing the benefits of DNS polling: 0 Cost: Just binding a few a records on the DNS server, domain registrars are generally Provides free parsing services, simple deployment: Device amplification in a network topology, and then add records to the DNS server. Disadvantages of DNS Polling: 1, low reliability assuming that a domain name DNS polls multiple servers, if one of the servers fails, then all requests to access the server will not respond, and this is something that no one would want to see. Even if the server's IP is removed from the DNS, but on the Internet, the regional telecommunications, netcom and other broadband providers to store a large number of DNS in the cache in order to save access time, the full effect of DNS records takes several hours, or even longer. Therefore, although DNS polling solves the problem of load balancing to some extent, it has the disadvantage of low reliability. 2, load distribution is not uniform DNS load balancing uses a simple polling algorithm, can not distinguish between server differences, can not reflect the current running state of the server, can not be a better performance of the server multi-allocation requests, and even the customer request to focus on a server situation. The DNS server is organized in a hierarchical structure, and the local DNS server caches the resolved domain name-to-IP-address mappings, which causes users who use the DNS server to access the same Web server over a period of time, resulting in uneven load between Web servers. Additionally, the user's local computer caches the resolved domain name-to-IP-address mappings. When multiple user computers cache a domain name-to-IP-address mapping, and these users continue to access the Web page under that domain name, this can also result in uneven load distribution between different Web servers. The possible consequences of a non-uniform load are the low load on some servers, the high load on the other servers, the slow processing of servers, the small number of requests allocated by the server with high configuration, and the many requests allocated by the low-profile servers.

Lab Environment:

1. 2 Web server systems Windows Server The IP is: 192.168.5.55 and 192.168.5.150

2. One DNS server system wind server ip:192.168.5.141

3. A single client ip:192.168.5.100

Lab Environment Configuration:

2 Web servers The process and steps to build the Web are no longer listed.

2. Make the following network configuration for each of the two Web servers to be interoperable:

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4. Build a DNS server to test the polling domain name as www.test.com

   {1. Build DNS: Double-click Server Manager to select Add roles

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8. Then click Next.

10. To adjust the configuration DNS server steps are as follows: 650) this.width=650; "Src=" http://s3.51cto.com/wyfs02/M00/58/E7/ Wkiom1taytzctyrqaaiswxkznqe133.jpg "title=" 11.jpg "alt=" Wkiom1taytzctyrqaaiswxkznqe133.jpg "/>

    
    

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26. The final configuration is displayed successfully such as:

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30. To test DNS polling:

32. On the test machine access www.test.com such as: (in 192.168.5.55 Web page content display www.test.com 192.168.5.55, The content displayed in the 192.168.5.150 Web page is www.test.com 192.168.5.100)

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36. To view DNS records:

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38. The nslookup directive can test if the DNS polling configuration is correct, such as: www.test.com corresponds to exactly the specified 2 Web

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42. After emptying the browser and DNS records, the re-access is positioned from 192.168.5.55 to 192.168.5.150:

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Configure DNS polling for a Windows environment (Simple load Balancing)