
Software User’s Manual Ver.A1D-502-V8.03.30-NB
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There however exists a solution that makes sure the NVR can find the camera even if the
camera IP changes frequently. Our cameras support Dynamic DNS or DDNS service that
allows frequently changing IP be mapped to a certain unchangeable domain name. The
mapping database and its updating engine are hosted in one of the Dynamic DNS servers,
most of which offer basic services for free, such as
www.dyndns.org
.
How does it work? Look at the graph below.
Every time the IP camera gets an IP that is different from previous one, it notifies the
public DDNS Service about the change. The DDNS Service updates its database
immediately, mapping the assigned domain name (for example camera123.dyndns.org) to
the new IP address. In NVR settings, only the domain name (camera123.dyndns.org) is
used to identify the camera. Every time when NVR needs to connect to the camera, it asks
from DDNS Service what the current camera
’
s IP is. The DDNS Service instantly responds
to NVR and tells it the camera
’
s IP. Now NVR will use the IP of the camera to connect to
the camera and the video stream from the camera to NVR can be initiated.
As a result, NVR can always find the IP camera regardless of frequently changing IP address
of the camera. Since there are so many public DDNS Services available for free, the PPPoE-
based connection is really a good and low-cost solution for single-camera sites.
Internet
Control Center
(NVR)
IP Camera
DSL Modem
Using Dynamic DNS
DDNS Service
Camera notifies DDNS service when IP changed
NVR uses camera
’s domain name to ask DDNS
DDNS tells the NVR what the camera
’s IP is
Commands from NVR to camera
’s IP address
Video Stream from camera to NVR