When deploying an Ubuntu 22.04 host, the corresponding PXELinux template holds two addresses:

• the iso image url (`http://foreman.example.com:80/pub/path/to/image.iso`)
• the userdata interface url (`http://foreman.example.com:80/userdata/`)

In order to reference these addresses in the template, the `@preseed_server` variable is used which links to `http://foreman.example.com:80`. This works fine for direct Foreman-based deployments.

If we want to deploy from a Smart Proxy now, a problem arises with the userdata interface: The Smart Proxy itself does not provide the userdata interface directly, but it forwards the request to the Foreman. The port to forward this request is by default `smart.proxy.com:8000`. Unfortunately, the `@preseed_server` variable contains the port `:80` which is wrong in this scenario.
In order to reference the template server, which is supposed to be used here, we must use the correct port. A different variable than `@preseed_server` must be used which holds the corresponding Smart Proxy port (by default :8000)