smbd

smbd [-D] [-F] [-S] [-i] [-o socket options] [-P] [-p port number] [-s configuration file] [-V] [-b]

-D
    Run as a daemon. This is the default behavior when smbd is started normally and not via inetd or similar service managers.

-F
    Run in the foreground. This option prevents the process from detaching from the controlling terminal, making it useful for debugging or when running smbd under a process supervisor like systemd.

-S
    Run as a single process instead of forking a new one for each client connection. This mode is primarily intended for debugging and testing purposes.

-i
    Run in interactive mode. This option is largely deprecated and may not be fully functional or supported in newer versions of Samba.

-o socket options
    Set specific socket options for the listening socket. Options are provided as a comma-separated list, affecting network communication behavior.

-P
    Do not daemonize. Similar in effect to -F, but generally deprecated in favor of using -F for foreground operation.

-p port number
    Listen on the specified port number instead of the default SMB ports (139 and 445). Useful for testing or running multiple Samba instances.

-s configuration file
    Specify the path to the Samba configuration file (smb.conf) to use. If not specified, smbd defaults to a standard system-wide path (e.g., /etc/samba/smb.conf).

-V
    Print the Samba version number to standard output and then exit.

-b
    Print Samba build options to standard output and then exit. This provides details about how the Samba binary was compiled.

smbd is the server daemon that provides file sharing and print services to SMB/CIFS clients. It operates as a core component of the Samba suite, enabling Linux and Unix-like systems to function as Windows file and print servers.

The daemon handles client connections, authenticating users, managing access to shared resources (directories and printers), and facilitating data transfer. For each client connection, smbd typically forks a new process to handle the request. Its behavior and the resources it shares are primarily defined by the smb.conf configuration file.

Proper and secure operation of smbd relies heavily on a correctly configured smb.conf file, which dictates shared resources, authentication, and security.
Network security is crucial; ensure firewalls are configured to allow necessary SMB/CIFS ports (typically 139/TCP, 445/TCP) only from trusted networks or hosts.
File system permissions on shared directories must be meticulously set to grant appropriate access to Samba users.
Performance can be sensitive to network latency, disk I/O capabilities, and overall server hardware specifications.

smbd's entire operational behavior, including which directories and printers are shared, user authentication methods, logging levels, and security settings, is controlled by the smb.conf file. This file is typically located at /etc/samba/smb.conf or /usr/local/samba/etc/smb.conf. Any modifications to this file usually require reloading or restarting the smbd service for the changes to take effect.

smbd generates detailed logs that are indispensable for troubleshooting and monitoring the service. The paths and verbosity of these logs are configured within the smb.conf file, allowing administrators to control the amount of information recorded, which is vital for diagnosing connection issues, permission errors, or other operational failures.

smbd is a foundational component of the Samba project, which was initiated by Andrew Tridgell in 1992. The project's primary aim was to create an open-source implementation of the Server Message Block (SMB) protocol, later known as Common Internet File System (CIFS), allowing Unix-like systems to seamlessly interoperate with Microsoft Windows networks for file and print sharing. Over the decades, smbd (and the entire Samba suite) has undergone continuous development, adapting to new Windows features, protocol versions, and security standards, evolving into a robust and widely adopted solution for cross-platform networking.

smb.conf(5), nmbd(8), samba(7), testparm(1), smbclient(1)