Windows machine lock/login screen misconfigured domain name

Just installed UCS 5.0-5 errata821 as a base for a brand new LAN.

Unsurprisingly, our domain corresponds to the org name and starts with a number e.g 3littlepigs.lan

We have created a UCS domain, added the “Active Directory-compatible Domain Controller” app and joined a test Windows 10 machine.

The problem I’m facing is that the windows/domain UCR variable is showing “littlepigs” rather the 3littlepigs.lan, and so the Windows client sees “Sign in to: littlepigs”.

Server error message:
The UCR variable windows/domain is read-only and can not be changed!

Any idea how to fix this?


Although this seemed relatively harmless as the Windows machine joined the domain and users are able to sign-in I found another issue.

If I try to access the system over LAN I’m prompted for a username and password, sure… problem is that the domain is not recognized and the workgroup must be used, eg.:
littlepigs\username rather the expected 3littlepigs\username

That’s confusing… any suggestions what will happen when I change the WORKGROUP in smb.conf and zone krb5.conf?