The "Alway bcc" option specifies an optional address that receives a copy of each message that enters the Postfix system, not including bounces that are generated locally. This option sets the "always_bcc" postfix variable.
The "Daemon timeout" option specifies how much time a daemon may take to handle a request before it assumes it is wedged and commits suicide. This option sets the "daemon_timeout" postfix variable.
The "Default database type" option specifies the default database type to use in postalias(1) and postmap(1) commands. On many UNIX systems the default type is either `dbm' or `hash'. The default is determined when the Postfix system is built. This option sets the "default_database_type" postfix variable.
The "Default transport" option specifies the default message delivery transport to use when no transport is explicitly given in the optional transport(5) table. This option sets the "default_transport" postfix variable.
The "Double bounce sender" option specifies the sender address for mail that must be discarded when it cannot be delivered. This must be a unique name. All mail to this name is silently discarded, in order to terminate mail bounce loops. This option sets the "double_bounce_sender" postfix variable.
The "Hash queue depth" option hash_queue_depth specifies the number of subdirectory levels below the queue directories listed in the "Hash queue names" option.
Multiple subdirectory levels can speed up directory access by reducing the number of files per directory. This option sets the "hash_queue_depth" postfix variable.
The "Hash queue names" option specifies the names of queue directories that are split across multiple subdirectory levels. Hashing MUST NOT be used with a world-writable maildrop directory. Hashing MUST be used for the defer logfile directory, or mail system performance will suffer.
Unfortunately, hashing the incoming or deferred queue can actually slow the mail system down (mailq with an empty queue can take several seconds) so it should be done only in case of emergency. This option sets the "hash_queue_names" postfix variable.
The "Hopcount limit" option limits the number of Received: message headers. A message that exceeds the limit is bounced. This option sets the "hopcount_limit" postfix variable.
The "Ipc idle" option bounds the idle time in seconds after which an internal IPC client disconnects. The purpose is to allow servers to terminate voluntarily. Currently this is used by the address resolving and rewriting clients. This option sets the "ipc_idle" postfix variable.
The "Ipc timeout" option specifies a timeout in seconds for I/O on internal communication channels. The purpose is to break out of deadlock situations. If the timeout is exceeded the software aborts with a fatal error. This option sets the "ipc_timeout" postfix variable.
The "Mail name" option specifies the mail system name that is used in Received: headers, in the SMTP greeting banner, and in bounced mail. This option sets the "mail_name" postfix variable.
The "Mail version" option specifies the official version of the mail system. The version string can be used in, for example, the SMTP greeting banner. This option sets the "mail_version" postfix variable.
The "Max idle" option limits the time in seconds that a Postfix daemon process waits for the next service request before exiting. This option is ignored by the Postfix queue manager. This option sets the "max_idle" postfix variable.
The "Max use" option limits the number of service requests handled by a Postfix daemon process before exiting. This option is ignored by the Postfix queue manager. This option sets the "max_use" postfix variable.
The "Notify classes" option specifies the list of error classes that are reported to the postmaster. The default is to report only the most serious problems. The paranoid may wish to turn on the policy (anti-UCE violations) and protocol error (broken mailers) reports. See the example bellow.
notify_classes = bounce,delay,policy,protocol,resource,software notify_classes = 2bounce,resource,software
The above options specify who gets postmaster notices if one of the above error conditions is recognized. All options default to "postmaster". This options sets the "bounce_notice_recipient", "2bounce_notice_recipient", "delay_notice_recipient" and "error_notice_recipient" postfix variables respectively.
The "Process id directory" option specifies a lock file directory relative to the Postfix queue directory. This facility is used by the master daemon to lock out other master daemon instances. This option sets the "process_id_directory" postfix variable.
The "Program directory" option specifies the location of Postfix support programs and daemons. This directory must be owned by root. This option sets "program_directory" postfix variable.
The "Sun mailtool compatibility" option disables kernel file locks on mailboxes. This is needed on SUN workstations because the mailtool program keeps an exclusive kernel lock while its window is open. SUN software uses user.lock files only. Unless you remove all SUN mail software, kernel locks just give a false sense of security. This option sets "sun_mailtool_compatibility" postfix variable.
The "Trigger timeout" option limits the time to send a trigger to a Postfix daemon. This prevents programs from getting stuck when the mail system is under heavy load. This option sets "trigger_timeout" postfix variable.
The "Delay warning timeout" option specifies after how many hours a warning is sent that mail has not yet been delivered. By default, no warning is sent. This option sets "delay_warning_time" postfix variable.