H3C Technologies H3C WX6000 Series Access Controllers - Manual (Page 226)

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DNS Configuration
Support of the H3C WX series access controllers for features may vary by device model. For more
information, see "Feature Matrixes" in Compatibility Matrixes.
The sample output in this manual was created on the WX5004. The output on your device may
vary.
The grayed out functions or parameters on the Web interface indicate that they are not supported
or cannot be modified.
The models listed in this manual are not applicable to all regions. Please consult your local sales
office for the models applicable to your region.
Overview
Domain Name System (DNS) is a distributed database used by TCP/IP applications to translate domain
names into corresponding IP addresses. With DNS, you can use easy-to-remember domain names in
some applications and let the DNS server translate them into correct IP addresses.
There are two types of DNS services, static and dynamic. After a user specifies a name, the device
checks the local static name resolution table for an IP address. If no IP address is available, it contacts
the DNS server for dynamic name resolution, which takes more time than static name resolution.
Therefore, some frequently queried name-to-IP address mappings are stored in the local static name
resolution table to improve efficiency.
Static Domain Name Resolution
Configuring static domain name resolution is to set up mappings between domain names and IP
addresses manually. IP addresses of the corresponding domain names can be found in the static
domain resolution table when you use applications such as telnet.
Dynamic Domain Name Resolution
Resolving procedure
Dynamic domain name resolution is implemented by querying the DNS server. The resolution
procedure is as follows:
1) A user program sends a name query to the resolver of the DNS client.
2) The DNS resolver looks up the local domain name cache for a match. If a match is found, it sends
the corresponding IP address back. If not, it sends a query to the DNS server.