User`s manual

phone. To reach Mary at the office, he needs to first dial the office’s phone #. If you are outside of the phone
system, you will have to first find a way to reach the system. This is the same for our networking example. To
access a remote network you will need to have its external IP address. However, unlike the difference between
a 10 digit phone # and a 3 digit extension #, the difference between local and external IPs are not as clear cut.
Both share the same format, therefore can cause some confusion. When you want to setup your security DVR
system to access remotely, you need to know both the local and external IP address.
There are several ways to find your external address:
1. Call your ISP (internet service provider) and ask them for it.
2. Check the status page of your router.
3. Or go to websites such as http://whatismyip.com/
If you have an active internet connection, the 3rd method is probably the easiest.
3c. Setting up Port Forwarding
OK, if you have followed everything mentioned in this guide so far, you should at least have the following:
1. Local IP address for your security DVR.
2. Port # for your security DVR.
3. External IP address for your network.
Going back to the phone system example in the previous section, if you are at home and you want to call
someone at the office, you will need to dial a phone # plus an extension #. However for networking, you will
need to specify the external IP address but NOT the local IP address. Instead, you will have to forward a port to
the local IP address. To do so, there is one extra setup step. I know we have already done plenty of setting-up
and you probably just want to finish with it; unfortunately, this is necessary, I’ll explain why:
Assuming that these are my IP addresses and the port #:
1. Local IP address for the DVR: 111.111.1.111
2. Port #: 5555
3. External IP: 22.222.22.22
If I want to access the security DVR remotely with a Java enabled browser, this is what I will need to type into
the location bar:
http://22.222.22.22:5555
As you have notice, no information on the local IP address was specified. When I press ENTER, a request will
travel through the web trying to reach the 22.222.22.22 IP address. Eventually, it will find the network. However,
when the request have reached the router it will no longer go any further. Why? Because the router does not
know how to handle this request. The router knows that the request is for port 5555, but does not know where
this port 5555 is going. In all of the previous sections, we had never done anything to allow the router to know
that port 5555 should be associated with local IP address 111.111.1.111. So in order for remote access, we have
to configure the router so that it knows where to forward that port. This step is called “Port Forwarding”.
Port forwarding is a feature of the router, therefore routers of different models and brands have different
interfaces for setting up this feature. I won’t be able to go through each and all of them here. Fortunately there is
a website dedicated to help people setting up port forwarding:
http://www.portforward.com/english/routers/port_forwarding/routerindex.htm
The site has a list of routers. Look for the brand of your router and then click on the specific model. You will then
see a list of applications; Avtech’s security DVRs are not on the list. However, setting up port forwarding is
similar for most applications. We’ll use the instructions for “ABC” software that is on the list (Fig. 11).