How secure is Samba4?

[Alex Besogonov]

Good $time_of_day!

I'm planning to deploy Samba4 on several sites (Samba4 will be limited to their
internal networks) and also on a central server with a public IPv4 and IPv6
addresses to serve as a central 'hub' for replication and Kerberos
authorization. So I have a question - how secure is Samba4?

Looking at the list of open ports, I guess it's not that much secure :) Is it
possible to turn off everything except Kerberos, LDAP and replication services?