Public Subdomain for local hosts

Networking DNS
1

Hi all,

i have a couple of devices for which I have configured static IP addresses that are distributed via DHCP. At the moment I use “localdomain” as the DHCP domain name for these. So from the internal network, I can reach device ABC using ABC.localdomain.

Now, I would like to allow the use of an SSL certificate obtained by let’s encrypt for my internal devices. I read that I can use a subdomain from one of my publicly available domains to obtain a certificate from let’s encrypt. Then I can deploy that certificate to my local devices and only need to make them available via the subdomain.

So, device ABC would need to be reachable from the internal network using the name ABC.subdomain.publicdomain.tld (resolving to the internal IP).

I tried to set the DHCP domain to subdomain.publicdomain.tld. But this didn’t work. The DNS resolver resolves this to the external IP of the subdomain.

Does anyone have an idea how to get around this? Or how to use let’s encrypt certificate for local devices together with IP fire?

Thanks in advance and best wishes.
Hendrik

2

Theoredically you can do that, but the certificate has to be a global type or some call it wildcard certificate, and you would have to change IPFire’s Domain to subdomain.example.com so if IPFire hostnmame was ipfire, then it would be ipfire.subdomain.example .com. and you would have to generate a cert with that name from your Public SSL and install it.

I just run my own in a cert system. But I have entertained making a switch os to complement IPFIre with certificate, network shares and time server support.
Even though a wildcard cert can do this, I run my own cert system because its cheaper than the cert as well as I can change it automatically several times a day if I want. I have mine set to once daily. Because it takes a couple of days for AI to break SSL,

3

This is what I did.
I setup A Docker running NPM (Nginx Proxy Manager)