H3C Technologies H3C WX3000E Series Wireless Switches - Manual (Page 81)

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IPv4 DNS configuration
This chapter includes these sections:
• DNS overview
• Configuring the IPv4 DNS client
• Configuring the DNS proxy
• Configuring DNS spoofing
• Displaying and maintaining IPv4 DNS
• IPv4 DNS configuration examples
• Troubleshooting IPv4 DNS configuration
NOTE:
•
The term "switch" or "device" in this chapter refers to the switching engine on a WX3000E wireless
switch.
• The WX3000E series comprises WX3024E and WX3010E wireless switches.
• The port numbers in this chapter are for illustration only.
DNS 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.
DNS services can be static or 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. To improve efficiency, you
can put frequently queried name-to-IP address mappings in the local static name resolution table.
Static domain name resolution
Static domain name resolution means setting up mappings between domain names and IP addresses. 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
Resolution process
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 the resolver finds a match,
it sends the corresponding IP address back. If not, it sends a query to the DNS server.