[Samba] How to add or modify msDS-PrincipalName Attribute

[James Atwell]

Hello,

     I'm attempting to use DUO for 2FA against a Samba 4.11.6 DC. on 
Ubuntu 16.04. I understand the OS and Samba is outdated. Everything goes 
well until the service user attempts to authenticate an AD user. The 
error from DUO is the service user is unable to fetch the 
msDS-PrincipalName. When I look at the attribute for the user I see it's 
missing. ADSI and ADUC does not let me modify.  Can I manually or auto 
add this for all users in the domain?

-James