That is, I want it to use just the local internal ip addresses (which can be internally resolved from domain names.) The will be an external IP address but I want it only for downloading apps and such. (And possibly mail) The normal installation wants an external domain for access. Can I get around this? Maybe by editing the DNS records after install?
Try to install with a domain like yunohost.local, it work for me on a virtual machine.
That’s more or less what I did, but it associates that name with my external ip address.