For a jail, following path are considered default configuration files:
- /etc/jail.conf
- /etc/jail.conf.d/<jail>.conf
- /etc/jail.<jail>.conf
Those files are now always parsed. If user specifies "-f /path/to/file", it is added to the list of configuration files. As wildcard jails (aka global parameters) can be defined in any of the configuration files, jail(8) has to parse them all to retain consistent behaviour when providing "-f" option.
To enable parsing of all configuration files, -F has to be added to jail_flags. To activate it in rc.d/jail, one has to add jail_config_file in rc.conf. The value of jail_config_file can be "single" or "multiple".