Using Berkeley DB Version 2 hash files. The hash file used is named after the namespace and is looked for in the directory that was given as argument when initializing the module. (default: /etc/popular/db/). An example: /etc/popular/db/test.db is the file for the namespace 'test'.
The lookup key in the DB file is the POP3 username. There is no trailing zero after the key or data. The data should be a colon separated list of the crypted password, the ID of the backend server and the mailbox name. A Perl script db-create.pl is supplied (along with example files) in the auth subdirectory to create this DB file from a text file containing lines with a colon separated list of username, crypted password, backend server name and mailbox. The 'source' file can contain empty lines and comment lines beginning with a '#' symbol.