tailieunhanh - Microsoft Press mcts 70 642 configuring windows server 2008 network infrastructure phần 3

Khi một máy chủ DNS nhận được một truy vấn, như thế nào cố gắng đầu tiên để giải quyết tên? 2. Nếu một máy chủ DNS không thể giải quyết một truy vấn bằng cách sử dụng phương pháp đầu tiên, nó sẽ sử dụng phương pháp tiếp theo? Kiểm tra nhanh chóng trả lời 1. | 108 Chapter 2 Configuring Name Resolution Quick Check 1. When a DNS server receives a query how does it first attempt to resolve the name 2. If a DNS server cannot resolve a query by using the first method which method will it use next Quick Check Answers 1. A DNS server first attempts to resolve a query by using resource records stored in a locally configured zone. 2. If a DNS server cannot resolve a query by using zone data it attempts to answer the query by using cached information. Understanding Recursion If the queried name does not find a matched answer at its preferred server either from its cache or zone information the query process continues in a manner dependent on the DNS server configuration. In the default configuration the DNS server performs recursion to resolve the name. In general recursion in DNS refers to the process of a DNS server querying other DNS servers on behalf of an original querying client. This process in effect turns the original DNS server into a DNS client. If recursion is disabled on the DNS server the client itself performs iterative queries by using root hint referrals from the DNS server. Iteration refers to the process of a DNS client making repeated queries to different DNS servers. Root Hints To perform recursion properly the DNS server first needs to know where to begin searching for names in the DNS domain namespace. This information is provided in the form of root hints a list of preliminary resource records used by the DNS service to locate servers authoritative for the root of the DNS domain namespace tree. By default DNS servers running Windows Server 2008 use a preconfigured root hints file that is stored in the WINDOWS System32 Dns folder on the server computer. The contents of this file are preloaded into server memory when the service is started and contain pointer information to root servers for the DNS namespace. Figure 2-8 shows the default root hints file. Lesson 1 Understanding Name Resolution in .