I use multiple devices to do port forwarding inside my network to multiple IP's. Each device either has a fixed IP, or uses DHCP, but is assigned a static IP by the router using its MAC address.
If you use an IP camera, either assign a fixed IP to it, or use the router's IP reservation feature via DHCP, then setup port forwarding to route from the external public IP/DNS to your internal private network. I use Netgear routers which has this feature, so do Trendnet. Limit DHCP IP range to not extend beyond fixed IP addresses.
My 2 Remoterigs use static fixed IP's and I assigned separate port numbers to each:
RemoteRig1 uses default ports:
RemoterigAudio 11000 192.168.0.228
RemoterigCmd 12000 192.168.0.228
RemoterigSIP 5060 192.168.0.228
RemoteRig2 uses next port number and different fixed IP:
RemoteRigAudio2 11001 192.168.0.230
RemoteRigCMD2 12001 192.168.0.230
RemoteRigSIP2 5061 192.168.0.230