I have configured DNS, NPT and active directory services on my server but I'm still struggling to connect FreeNAS to a domain. There is no firewall between these two. I've created a freenasAdmin user and added a new computer with all the necessary privileges. There is no adminui nor nis feature anymore in 2016 so I'm not quite sure I did it right. All the FreeNAS throws at me is can't connect o ldap connection timeout.
I suppose you have a working Windows 2016 DC so I won't go into that.
In FreeNAS go to directory services -> active directory and click Advanced Mode.
- Enter your domain name, Domain acc. and password (I used Administrator acc)
- uncheck UNIX extensions
- enter your site name (this can be found in server manager -> Tools -> Active Directory Sites and Services)
- enter FQDN of your DC and GC
- set Idmap backend to rip and SASL wrapping to sign
- check enable
- enter netBIOS name capitalized and hit save