SELinux is based on the least level of access required for a service to run. Services can be run in a variety of ways; therefore, you must tell SELinux how you are running services. The following Boolean allows you to tell SELinux how you are running Postfix:
allow_postfix_local_write_mail_spool
Having this Boolean enables Postfix to write to the local mail spool on the system. Postfix requires this Boolean to be enabled for normal operation when local spools are used.
