Where things are placed ?

/etc/ze-filter - Configuration files;
/var/ze-filter - Let's call this the HOME DIR or where ze-filter does the most of his job. Directories inside :
- cdb - static (constant) databases, opened in read-only mode by the filter : policy database, valid recipients database, bayes database, …
- wdb - working databases, where the filter stores live data such as greylisting data, dns resolution, …
- ze-greydb - working databases used by ze-greyd (centralized greylisting) daemon;
- files - flat text and binary files generated by the filter;
- bin - some small tools and scripts useful to manage the filter or the data generated by it;
- dbtools - BerkeleyDB tools (ze-db_recover, ze-db_upgrade, …) compiled with the filter and with the same library version of the filter.
/var/spool/ze-filter - The filter creates, in this directory, temporary files with the contents of the messages being handled.