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?

Update…

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?

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