Cannot open port through Airport Extreme to access security system DVR

Question

I have internet access through Bellsouth DSL -- modem only. We had a security system set up around a DVR recording images and connected to the internet through a Linksys router. We would use a client on outside computers to connect to the security system dvr and see what was happening (live or recorded). I switched out the Linksys for the Airport Extreme, and now we cannot connect to the DVR.
Do I need to manually open a port to the DVR? How do I do this? The DVR connects to the Airport Extreme via Ethernet, and as far as I can tell, the Airport Extreme connects to the DSL modem via Ethernet using DHCP. We have a static IP address. I thank you in advance for any answers, and I apologize if I'm not giving enough information.

Answer 1

Let's double-check your Port Mapping setup on the 802.11n AirPort Extreme Base Station (AEBSn) ...
To setup port mapping on an 802.11n AirPort Extreme Base Station (AEBSn), either connect to the AEBSn's wireless network or temporarily connect directly, using an Ethernet cable, to one of the LAN port of the AEBSn, and then use the AirPort Utility, in Manual Setup, to make these settings:
1. Reserve a DHCP-provided IP address for the host device.
Internet > DHCP tab
o On the DHCP tab, click the "+" (Add) button to enter DHCP Reservations.
o Description: <enter the desired description of the host device>
o Reserve address by: MAC Address
o Click Continue.
o MAC Address: <enter the MAC (what Apple calls Ethernet ID if you are using wired or AirPort ID if wireless) hardware address of the host computer>
o IPv4 Address: 10.0.1.4
o Click Done.
2. Setup Port Mapping on the AEBSn.
Advanced > Port Mapping tab
o Click the "+" (Add) button
o Service: <choose the appropriate service from the Service pop-up menu>
o Public UDP Port(s): 6746
o Public TCP Port(s): 6746
o Private IP Address: 10.0.1.4
o Private UDP Port(s): 6746
o Private TCP Port(s): 6746
o Click "Continue"