COMPRO NC420 User Manual page 67

Symptom
The entered hostname/WAN IP address is incorrect.
Make sure you entered the correct hostname (if you use iDDNS) or the WAN IP address of
your camera in the location field of the web browser.
The LAN network is not connected to Internet.
You need to have access to the Internet when trying to view your network camera
remotely. Equally, your camera installed on a LAN network also needs to have access
to the Internet for your camera to be accessed remotely. Check if you can browse the
Internet on your LAN network with your PC. If not, contact your network administrator
for assistance.
The camera's WAN IP address has changed but yet to be updated into DNS cache.
If you use DDNS service, the information of your camera's IP address and the domain
name the IP address is linked to is stored in the DNS cache. The cache is used to
S u c c e s s f u l a c c e s s
retrieve the IP information by the DNS server which translates entered hostname into
o n l o c a l n e t w o r k ,
the camera's IP addressand. Though the information is updated every few minutes
but having problem
(determined by the value of TTL, Time to Live), occassionally the DNS information
a cce s s i n g ove r t h e
changes (e.g. your camera acquires new IP) but the old information is still stored in the
Internet.
cache., resulting in connection failure.
When this happens, try wait a few minutes for the new IP information to be updated
onto DNS server and then retry connection, or try to decrease the TTL value. If it still
doesn't work, refer to other possible causes and solutions, or contact Compro for
technical support.
The router's configuration does not allow incoming traffic to the camera.
If you want to make your camera located on a LAN network accessible from the Internet,
you need to enable port forwarding on your router and allow incoming traffic on the
HTTP and RTSP ports your camera is using (your router may require a reboot after port
forwarding is set). Refer to the "Remote Viewing via Internet Explorer" section in the user
manual for detailed information. If you don't know how to enable port forwarding on
the router, consult the manufacturer of your router for instruction.
Possible Cause/Solution
Symptoms, Causes and Solutions 9-9
Chapter 9: Troubleshooting