數(shù)據(jù)通信與網(wǎng)絡chapter25

1、25.1Chapter 25Domain Name SystemCopyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.25.2Figure 25.1 Example of using the DNS service25.3Flat Name SpaceHierarchical Name Space25.4LabelDomain NameDomain25.5Figure 25.2 Domain name space25.6Figure 25.3 Domain names

2、and labels25.7Figure 25.4 FQDN and PQDN25.8Figure 25.5 Domains25.9Hierarchy of Name ServersZoneRoot ServerPrimary and Secondary Servers25.10Figure 25.6 Hierarchy of name servers25.11Figure 25.7 Zones and domains25.12A primary server loads all information from the disk file; the secondary serverloads

3、 all information from the primary server. When the secondary downloadsinformation from the primary, it is called zone transfer.Note25.13Generic DomainsCountry DomainsInverse Domain25.14Figure 25.8 DNS IN THE INTERNET25.15Figure 25.9 Generic domains25.16Table 25.1 Generic domain labels25.17Figure 25.

4、10 Country domains25.18Figure 25.11 Inverse domain25.19ResolverMapping Names to AddressesMapping Addresses to NamesRecursive ResolutionCaching25.20Figure 25.12 Recursive resolution25.21Figure 25.13 Iterative resolution25.22Header25.23Figure 25.14 Query and response messages25.24Figure 25.15 Header format25.25Question RecordResource Record25.2625.2725.2825.29DNS ca