How do I open ports on my airport extreme and assign a fixed IP Address for a device connected to my network?

Question

I recently had a security system installed in my house.  One of the features is an EPAD which enables me to have a virtual keypad on my iphone, and computer to operate the alarm system.  The technician was not familiar with Mac's and Airports.  How do I open port 80 to 80 in my airport and assign a fixed IP address for the EPAD?  Apparently this is what is needed to make this work.

Answer 1

There are three ranges of "strictly local" IP addresses reserved for local Network use:
192.168.xxx.yyy
172.16.xxx.yyy
10.xxx.yyy.zzz
What your Router does for you is to act as your agent on the Internet.Your requests are packaged up and forwarded on your behalf, and only when a response is expected is the response returned to your local IP address.
Directing Network Traffic to a Specific Computer on Your
Network (Port Mapping)
AirPort Extreme uses Network Address Translation (NAT) to share a single IP address with the computers that join the AirPort Extreme network. To provide Internet access to several computers with one IP address, NAT assigns private IP addresses to each computer on the AirPort Extreme network, and then matches these addresses with port numbers. The wireless device creates a port-to-private IP address table entry when a computer on your AirPort (private) network sends a request for information to the Internet.
If you’re using a web, AppleShare, or FTP server on your AirPort Extreme network, other computers initiate communication with your server. Because the Apple wireless device has no table entries for these requests, it has no way of directing the information to the appropriate computer on your AirPort network.
To ensure that requests are properly routed to your web, AppleShare, or FTP server, you need to establish a permanent IP address for your server and provide inbound port mapping information to your Apple wireless device.
To set up inbound port mapping:
1) Open AirPort Utility, select your wireless device, and then choose Base Station > Manual Setup, or double-click the device icon to open its configuration in a separate window. Enter the password if necessary.
2) Click the Advanced button, and then click Port Mapping.
3) Click the Add button and choose a service, such as Personal File Sharing, from the Service pop-up menu.