Yeah, this was the whole problem I was having.

I've solved the issue now, I have a Raspberry Pi connected with POE to my switch and I've installed Caddy on that and have that set up to proxy internal sites, my main server is running another instance of caddy which exposes external services.

Working like a charm.

I did try to use the Synology, but it's a clusterf**k on that, it regenerates config files at boot and it has a proxy service running on port 80 which you can't disable, so I played around for a couple of hours, got nowhere and pulled the pi out of a box and had it running within an hour or so.