User Authentication with Samba

This book has concentrated on Unix services, with only a few exceptions; email applications often cross platform boundaries, as do requirements for file and printer sharing. The Samba project ( has become a staple for administrators seeking to integrate Unix file and print servers with Windows clients. Samba is a suite of programs that implement the server portion of the SMB (Server Message Block) protocol, later renamed CIFS (Common Internet File System).

Samba includes several client programs and administrative tools in addition to its server components. Adequate coverage of Samba is well beyond the scope of this book. For more information about Samba, see Sams Teach Yourself Samba in 24 Hours, Second Edition, by Gerald Carter (Sams Publishing), or Using Samba, Second Edition, by Jay Ts, Robert Eckstein, and David Collier-Brown (O’Reilly).

To support the challenge/response authentication methods used by Microsoft clients, Samba requires a list of hashed passwords separate from the normal Unix account information stored in /etc/passwd (or in the posixAccount object class). This collection of LanManager and Windows NT password hashes is normally stored in a file named smbpasswd(5); the format of each entry is:


Samba’s smbpasswd file has several disadvantages for sites with many users:

  • Lookups are performed sequentially. When servicing a domain logon request from a Windows NT/2000/XP ...

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