Bit of a followup to my previous post. I now have a VPS with nginx working as a reverse proxy to some services on my DMZ. My router (UDM pro) is running a wireguard server and the VPS is acting as a client.
I’ve used Letsencrypt to get certs for the proxy, but the traffic between the proxy and the backend is plain HTTP still. Do I need to worry about securing that traffic considering its behind a VPN? If I should secure it, is there an easier way to do self-signed certs besides spinning up your own certificate authority? Do self-signed certs work between a proxy and a backend, or would one or the other of them throw a fit like a browser does upon encountering a self-signed cert?
I’d rather not have to manage another set of certs just for one service, and I don’t want to involve my internal domain if possible.


Question, how do you deal with the certificates if you have an external vps doing passthroy?
Because that certificate will not match the domain name of the vps and then everything will fail or at least trigger a lot of alerts.
I really fail to see how an internal backend in a different subnet can send the right certificate
There’s no certificate at the VPS level. It forwards everything to and from the self hosted reverse proxy.
Now that you mention it though, there may be a slight complication with pinning the reverse proxy to the domain API for cert renewals. I’ll have to check how I have mine configured but I may have given my reverse proxy a IPv6 and configured that for cert renewals.
That would mean some down time as you update the IP if your ISP rotates it.