We have 8x IP CCTV Cameras and 1x NAS for recording on a LAN (with an internal address range) and port forwarding from a single WAN address to connect to each. For instance, by connecting to port 8009 on the WAN IP we can access the NAS, connecting to port 8008 on the WAN IP connects to camera 8, etc.
The software for connecting to the CCTV cameras and NAS only allows one IP address to be entered (the external one). We used to only access the cameras/NAS whilst external from the building, so this worked fine. However now we may be on the LAN itself, and the Cisco Router/Firewall isn't performing the port forwarding magic we need (it drops the packets).
How do you get a Cisco Router/Firewall to honour WAN IP + Port Forwarding whether you are on the LAN or external?
Your problem is analogous to the one clearly described here, as well as to the one answered here. In essence, you need to configure "hairpin NAT" on your router, which will likely involve adding one or more source NAT rules to your router's configuration. Sorry I can't be more specific, but I am not familiar with Cisco hardware.