Not completely. Samba domain control capabilities for a Windows 9x client are solid and complete, and so these clients would probably never know the difference. The domain control support for Windows NT/2000 clients is still being developed. Currently, enough has been implemented to allow a Windows NT client to join a Sambacontrolled domain, but there is more to domain control than that. The most conspicuous absence is the lack of support for Windows NT trust relationships and the SAM replication protocol used between NT PDCs and Backup Domain Controllers (BDCs).