I have a product that uses an IP camera and a simple ATmega-based motherboard for general I/O control, managing a very simple web interface, etc. Ideally, I would like to be able to access both of these devices (the IP camera web interface and the custom simple motherboard web app) through one single external IP address.
Note: the microcontroller only needs 1 or 2 very basic external commands. A small hosted web page is of course a nice solution, but if there was a simple way just to send a couple of digital signals to the microcontroller that would be sufficient.
So far, I have been able to achieve simultaneous communication with both through a simple layer-2 ethernet switch. Of course, the simple switch doesn't have the ability to assign "internal" IP addresses (like a layer-3 router running DHCP), so two separate "external" IP addresses were used to communicate with the individual devices.
What is the simplest/best way to achieve what I'm looking for while taking up only 1 "externally-accessible" IP address?
Links I've come across so far with some solutions are below, but there may definitely be a much better solution that I haven't come across yet.
I've also attached a top-level diagram of my topology, seen below.
Thanks in advance for any help!