Sets the type of database file that is used to store the passwords.
The default database type is determined at compile time. The
availability of other types of database files also depends on
compile-time settings.
It is crucial that whatever program you use to create your password
files is configured to use the same type of database.

The AuthDBMUserFile directive sets the
name of a DBM file containing the list of users and passwords for
user authentication. File-path is the absolute path to
the user file.
The user file is keyed on the username. The value for a user is
the 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 AuthDBMUserFile 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 AuthDBMUserFile.
Important compatibility note: The implementation of
dbmopen in the apache modules reads the string length of
the hashed values from the DBM 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 DBM files
interchangeably between applications this may be a part of the
problem.
A perl script called
dbmmanage is included with
Apache. This program can be used to create and update DBM
format password files for use with this module.