Samba-3 can participate in Samba-to-Samba as well as in Samba-to-MS Windows NT4-style trust relationships. This imparts to Samba scalability similar to that with MS Windows NT4.

Given that Samba-3 can function with a scalable backend authentication database such as LDAP, and given its ability to run in primary as well as backup domain control modes, the administrator would be well-advised to consider alternatives to the use of interdomain trusts simply because, by the very nature of how trusts function, this system is fragile. That was, after all, a key reason for the development and adoption of Microsoft Active Directory.