Simplest way to achieve single IP communication with IP camera and simple MCU?

Question

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.

• https://www.quora.com/Is-it-possible-for-a-network-switch-to-act-as-a-dhcp-server
• https://www.directindustry.com/prod/mpl/product-33713-2236421.html

I've also attached a top-level diagram of my topology, seen below.

Thanks in advance for any help!

Answer 1

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.

For that you need either a reverse proxy (which is off-topic here for working above the transport layer), or a router using port forwarding aka destination NAT aka reverse NAT from different, LAN-side TCP ports.

A DHCP server is required for those devices to get an automatically assign IP address (in contrast to a locally configured, static address). DHCP doesn't help with accessing both through a single address though.

In any case, for connecting both devices and the router or proxy you'll need a switch as well. Some (larger) switches can act as DHCP servers as well, so can many routers.

Of course, there's a large number of different ways to do it. If you run code on the MCU you could have it pick up the data from the camera and put it on its own web page (similar to a proxy, off-topic here). Or you could build a HTML frame set that simply creates a combined page from both (also off-topic here, but likely the simplest approach).