Chapter 1 Dns Configuration; Dns Overview; Static Domain Name Resolution; Dynamic Domain Name Resolution - Huawei Quidway S5600 Series Operation Manual

Operation Manual - DNS
Quidway S5600 Series Ethernet Switches-Release 1510

Chapter 1 DNS Configuration

When configuring DNS, go to these sections for information you are interested in:

DNS Overview

Configuring Static Domain Name Resolution
Configuring Dynamic Domain Name Resolution
Displaying and Maintaining DNS
Troubleshooting DNS Configuration
1.1 DNS Overview
Domain name system (DNS) is a mechanism used for TCP/IP applications such as
Telnet to convert Internet addresses in mnemonic form into the equivalent numeric IP
addresses.
There are two types of DNS services, static and dynamic. Each time the DNS Server
receives a name query it checks its static database before looking up the dynamic
database. Reduction of the searching time in the dynamic database would increase
efficiency. Some frequently used addresses can be put in the static database.

1.1.1 Static Domain Name Resolution

The static domain name resolution manually sets up mappings between names and IP
addresses. IP addresses of the corresponding names can be found in the static domain
name resolution database for applications.

1.1.2 Dynamic Domain Name Resolution

I. Resolving procedure
Huawei-3Com's router supports the following dynamic domain name resolution
procedures. The relationships of the user program, DNS Client and DNS Server are
shown in Figure 1-1.
1) A user program sends a name query to the resolver in the DNS Client.
2) The DNS resolver looks up its cache for a match. If one is found, it sends the
corresponding IP address back. If not, it sends a query to the DNS Server.
3) The DNS Server looks up its database for a match. If no match is found, it sends a
query to its parent DNS Server. If the parent DNS Server does not have the
information, it sends the query to yet another server. This process continues until a
result is found, either successful or fail.
4) The DNS Client performs the next operation according to the result.
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Chapter 1 DNS Configuration