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.
In regards to compatibility, 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.