The following is a brief introduction to the individual Samba daemons and services.
Samba is comprised of three daemons (smbd, nmbd, and winbindd). Two services (smb and
windbind) control how the daemons are started, stopped, and other service-related features. Each daemon is listed in detail, as well as which specific service has control over it.
The smbd server daemon provides file sharing and printing services to Windows clients. In addition, it is responsible for user authentication, resource locking, and data sharing through the SMB protocol. The default
ports on which the server listens for SMB traffic are TCP ports 139 and 445.
The smbd daemon is controlled by the smb service.
The nmbd server daemon understands and replies to NetBIOS name service requests such as those produced by SMB/CIFS in Windows-based systems. These systems include Windows 95/98/ME, Windows NT, Windows 2000, Windows XP, and LanManager clients. It also participates in the browsing protocols that make up the Windows Network Neighborhood view. The default port that the server listens to for NMB traffic is UDP port 137.
The nmbd daemon is controlled by the smb service.
The winbind service resolves user and group information on a server running Windows NT 2000 or Windows Server 2003. This makes Windows user / group information understandable by UNIX platforms. This is achieved by using Microsoft RPC calls, Pluggable Authentication Modules (PAM), and the Name Service Switch (NSS). This allows Windows NT domain users to appear and operate as UNIX users on a UNIX machine. Though bundled with the Samba distribution, the winbind service is controlled separately from
the smb service.
The winbindd daemon is controlled by the winbind service and does not require the smb service to be started in order to operate. Winbindd is also used when Samba is an Active Directory member, and may also be used on a Samba domain controller (to implement nested groups and/or interdomain trust). Because winbind is a client-side service used to connect to Windows NT-based servers, further discussion of winbind is beyond the scope of this manual.
