I have a defender security system and an Airport Extreme. How do I set up Network Sharing and Port forwarding with these?

To start do you have any issues with the system on our local network? That is, can you monitor the cameras while connected to the local network?

Does this security camera system use IP cameras? That is, do you access a camera via an IP address?

Does the manufacturer provide detailed instructions on which ports are required to access these cameras from a remote location? If so, what are they? They would be listed a either or both UDP or TCP ports.

Is your AirPort Extreme the only router in your current network configuration? ... or is it connected to another router upstream of it? Regardless, what is the exact model of your Extreme and the Internet modem that it is directly connected to?

Finally what Operating System is the computer running that you are using to administer the Extreme with?

The manufacturer provides instructions but they don't seem to be helping. They keep mentioning that I have to use port forwarding. The DVR has 3 ports mentioned: 18004, 5000, and 9000. I have set them all up to be port forwarded in the menu of the airport extreme according the apple's tech help desk. The same page with DHCP reservation menu. Those ports don't seem to be forwarding though. I have checked with several tools as well to see if the ports are open to no avail.

The key is that your AirPort Extreme must be reachable from the Internet. That means your ISP must provide you with either a static or dynamic Public WAN-side IP address and not one from their own private pools.

A way to verify this is to temporarily place the DVR in a DMZ instead of using port mapping. This would open all ports to the DVR. If the DVR is still not reachable then you will need to discuss this with your ISP. Apple calls the DMZ a "default host." You will find this option under Network Options on the Network tab of the AirPort Utility.

They also stated that I couldn't use port forwarding with the modem that I had right now.

That is correct. This modem, since it does not have a firewall, cannot be configured for port mapping.

Granted this modem I purchased myself

Shouldn't be a problem unless your ISP does not support this modem and it looks like they already do.

Anyway, it's my understanding that port forwarding is with the router, not the modem. Am i correct in thinking that?

That is correct.

I also tried the DMZ default host optiion on my router as well. When I clicked the option it entered the IP of 10.0.1.253. I checked the port 5000 after I tried that as well and it still stated that it was closed.

If that is the correct private IP address of the DVR then that is the correct address to put in the default host field in the AirPort Utility.

However, when you are attempting to access the DVR from the Internet on port 5000, you would enter the Public IP address of the router, not the private IP address of the DVR. For example, if you are accessing the web-based administration of the DVR, you would enter something like: http://123.456.789.123:5000, NOT http://10.0.1.253:5000.

Okay, so when using default host I would enter the IP address of the DVR which is 10.0.1.201, and it is set as static to stay that way. So I would enter 10.0.1.201 into the field, correct?

Yes, that is correct. For either setting up a default host or for port mapping you want to enter the local IP address of the host device. Entering this address in the default host field would open all the router's firewall ports to only this device, leaving it completely exposed to the Internet.

Using your "variant" addresses, when at a remote location, you should be able to access this DVR's web-page, by entering: http://75.142.198.222 in a web browser.

did you ever solve this problem I'm having the same issue