With Bacula Enterprise 12.0 and Bacula Community 11.0 comes a very useful new feature. Client or FD behind a NAT can now initiate the connection to the Director so the Director can start a new job on this client. It is very useful when the Director cannot connect to the FD. Obviously, it is still possible to schedule backup jobs. It also supports the "estimate" and "status client" commands. The new directive is called "Connect To Director".
For more information, please check the dedicated chapter to this new feature: https://www.bacula.org/11.0.x-manuals/en/main/New_Features_in_11_0_0.html#SECTION002300000000000000000.