Configuring Ddns; Overview; Ddns Application - HP FlexNetwork MSR2003 Configuration Manual

Configuring DDNS

Overview

DNS provides only the static mappings between domain names and IP addresses. When the IP
address of a node changes, your access to the node fails.
Dynamic Domain Name System (DDNS) can dynamically update the mappings between domain
names and IP addresses for DNS servers.
DDNS is supported only by IPv4 DNS, and it is used to update the mappings between domain names
and IPv4 addresses.

DDNS application

As shown in
•
DDNS client—A device that needs to update the mapping between its domain name and IP
address dynamically on the DNS server when its IP address changes. An Internet user typically
accesses an application layer server such as an HTTP server or an FTP server by using the
server's domain name. When its IP address changes, the application layer server runs as a
DDNS client. It sends a request to the DDNS server for updating the mapping between its
domain name and its IP address.
•
DDNS server—Informs the DNS server of latest mappings. When receiving the mapping
update request from a DDNS client, the DDNS server tells the DNS server to re-map the
domain name and the IP address of the DDNS client. Therefore, the Internet users can use the
same domain name to access the DDNS client even if the IP address of the DDNS client has
changed.
Figure 55 DDNS application
HTTP server
DDNS client
With the DDNS client configured, a device can dynamically update the latest mapping between its
domain name and IP address on the DNS server through DDNS servers.
NOTE:
The DDNS update process does not have a unified standard but varies by DDNS server that the
DDNS client contacts.
Figure 55, DDNS works on the client-server model.
DNS server
IP network
DDNS server
HTTP client
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