The AuthDBUserFile directive sets the name of a DB file containing the list of users and passwords for user authentication. Filename is the absolute path to the user file.
The user file is keyed on the username. The value for a user is the crypt() encrypted password, optionally followed by a colon and arbitrary data. The colon and the data following it will be ignored by the server.
Security: make sure that the AuthDBUserFile is stored outside the document tree of the web-server; do not put it in the directory that it protects. Otherwise, clients will be able to download the AuthDBUserFile.
Important compatibility note: The implementation of "dbmopen" in the apache modules reads the string length of the hashed values from the DB data structures, rather than relying upon the string being NULL-appended. Some applications, such as the Netscape web server, rely upon the string being NULL-appended, so if you are having trouble using DB files interchangeably between applications this may be a part of the problem.
See also AuthName, AuthType and AuthDBGroupFile.