Look up the whitelist command, you’ll need to whitelist your local IP/range or the port you want.
Maybe I missed it, where is the DNS server in this story?
You can download the evaluation copies of Windows Server directly from Microsoft. They are licensed for 180 days.
As the French say… Bonjour!
Where did you set the DNS server on your router for the clients? Did you set it in DHCP options?
Are you talking about bare metal or virtual machines?
Bare Metal I used Microsoft SCCM. It’s a pain to manage but when it works right you can easily use Task Sequences to deploy images with PXE boot.
I also had a previous install of Dell Open Enterprise Manager.
VMs, anything like Terraform and Ansible will work to deploy an image.
What typically happens here is you sysprep the machine and then you would convert it to an image. In enterprise, we'd create this "golden image" and then whenever we pass automation to create a VM we specify the use of that image. Once the image is in the right state, you should be able to select that image and then say "new VM from Image" or something similar to that. I'm speaking in generic terms, but Hyper-V can do this.
Capture image using DISM is basically how you do this when you need to do this for hardware via USB.
I once had a Senior Infrastructure Engineer looking at the logs of our public VPN host. A VPN host that is open to the world on 0.0.0.0/0 because that's the requirement we had. This Engineer saw thousands of failed login attempts to the VPN; things like admin/admin admin/password1 etc. Regular internet crap, a bot will scrape the web page and try its luck then move on.
This person then decided to initiate security breach procedure and immediately shut down the VPN, because "we'd been hacked!".
There's a lot of noise on the internet. The challenge is working out the best way to isolate your resources just enough and block anything that doesn't need access. This is why things like Web Application Firewalls exist.
Well, being able to change the name servers of a DDNS service would be very difficult unless they offer you the option to split the subdomain out.
If you're going to be doing this for a while, why not just buy a super cheap domain on sale? You can pick some domains up for like $1 when registrars are doing sales.