The Postfix main.cf configuration file specifies a small subset
of all the parameters that control the operation of the Postfix
mail system. Parameters not specified in main.cf are left at their
default values.
The general format of the main.cf file is as follows:
*
Each logical line has the form "parameter = value".
Whitespace around the "=" is ignored, as is whitespace at the
end of a logical line.
*
Empty lines and whitespace-only lines are ignored, as are lines
whose first non-whitespace character is a `#'.
*
A logical line starts with non-whitespace text. A line that starts
with whitespace continues a logical line.
*
A parameter value may refer to other parameters.
*
The expressions "$name", "${name}" or "$(name)" are
recursively replaced by the value of the named parameter.
*
The expression "${name?value}" expands to "value" when
"$name" is non-empty. This form is supported with Postfix
version 2.2 and later.
*
The expression "${name:value}" expands to "value" when
"$name" is empty. This form is supported with Postfix
version 2.2 and later.
*
When the same parameter is defined multiple times, only the last
instance is remembered.
*
Otherwise, the order of main.cf parameter definitions does not matter.
The remainder of this document is a description of all Postfix
configuration parameters. Default values are shown after the
parameter name in parentheses, and can be looked up with the
"postconf -d" command.
Note: this is not an invitation to make changes to Postfix
configuration parameters. Unnecessary changes can impair the
operation of the mail system.
2bounce_notice_recipient (default: postmaster)
The recipient of undeliverable mail that cannot be returned to
the sender. This feature is enabled with the notify_classes
parameter.
access_map_reject_code (default: 554)
The numerical Postfix SMTP server response code when a client
is rejected by an access(5) map restriction.
Do not change this unless you have a complete understanding of RFC 821.
Overrides the local_transport parameter setting for address
verification probes.
This feature is available in Postfix 2.1 and later.
address_verify_map (default: empty)
Optional lookup table for persistent address verification status
storage. The table is maintained by the verify(8) service, and
is opened before the process releases privileges.
By default, the information is kept in volatile memory, and is lost
after "postfix reload" or "postfix stop".
Specify a location in a file system that will not fill up. If the
database becomes corrupted, the world comes to an end. To recover
delete the file and do "postfix reload".
This feature is available in Postfix 2.1 and later.
address_verify_negative_cache (default: yes)
Enable caching of failed address verification probe results. When
this feature is enabled, the cache may pollute quickly with garbage.
When this feature is disabled, Postfix will generate an address
probe for every lookup.
This feature is available in Postfix 2.1 and later.
address_verify_negative_expire_time (default: 3d)
The time after which a failed probe expires from the address
verification cache.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
This feature is available in Postfix 2.1 and later.
The time after which a successful address verification probe needs
to be refreshed. The address verification status is not updated
when the probe fails (optimistic caching).
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
This feature is available in Postfix 2.1 and later.
Overrides the relay_transport parameter setting for address
verification probes.
This feature is available in Postfix 2.1 and later.
address_verify_relayhost (default: $relayhost)
Overrides the relayhost parameter setting for address verification
probes. This information can be overruled with the transport(5) table.
This feature is available in Postfix 2.1 and later.
address_verify_sender (default: postmaster)
The sender address to use in address verification probes. To
avoid problems with address probes that are sent in response to
address probes, the Postfix SMTP server excludes the probe sender
address from all SMTPD access blocks.
Specify an empty value (address_verify_sender =) or <> if you want
to use the null sender address. Beware, some sites reject mail from
<>, even though RFCs require that such addresses be accepted.
Overrides the sender_dependent_relayhost_maps parameter setting for address
verification probes.
This feature is available in Postfix 2.3 and later.
address_verify_service_name (default: verify)
The name of the verify(8) address verification service. This service
maintains the status of sender and/or recipient address verification
probes, and generates probes on request by other Postfix processes.
The alias databases that are used for local(8) delivery. See
aliases(5) for syntax details.
The default list is system dependent. On systems with NIS, the
default is to search the local alias database, then the NIS alias
database.
If you change the alias database, run "postalias /etc/aliases"
(or wherever your system stores the mail alias file), or simply
run "newaliases" to build the necessary DBM or DB file.
The local(8) delivery agent disallows regular expression substitution
of $1 etc. in alias_maps, because that would open a security hole.
The local(8) delivery agent will silently ignore requests to use
the proxymap(8) server within alias_maps. Instead it will open the
table directly. Before Postfix version 2.2, the local(8) delivery
agent will terminate with a fatal error.
Restrict local(8) mail delivery to external commands. The default
is to disallow delivery to "|command" in :include: files (see
aliases(5) for the text that defines this terminology).
Specify zero or more of: alias, forward or include,
in order to allow commands in aliases(5), .forward files or in
:include: files, respectively.
Example:
allow_mail_to_commands = alias,forward,include
allow_mail_to_files (default: alias, forward)
Restrict local(8) mail delivery to external files. The default is
to disallow "/file/name" destinations in :include: files (see
aliases(5) for the text that defines this terminology).
Specify zero or more of: alias, forward or include,
in order to allow "/file/name" destinations in aliases(5), .forward
files and in :include: files, respectively.
Example:
allow_mail_to_files = alias,forward,include
allow_min_user (default: no)
Allow a recipient address to have `-' as the first character. By
default, this is not allowed, to avoid accidents with software that
passes email addresses via the command line. Such software
would not be able to distinguish a malicious address from a
bona fide command-line option. Although this can be prevented by
inserting a "--" option terminator into the command line, this is
difficult to enforce consistently and globally.
allow_percent_hack (default: yes)
Enable the rewriting of the form "user%domain" to "user@domain".
This is enabled by default.
Note: with Postfix version 2.2, message header address rewriting
happens only when one of the following conditions is true:
*
The message is received with the Postfix sendmail(1) command,
*
The message is received from a network client that matches
$local_header_rewrite_clients,
*
The message is received from the network, and the
remote_header_rewrite_domain parameter specifies a non-empty value.
To get the behavior before Postfix version 2.2, specify
"local_header_rewrite_clients = static:all".
Example:
allow_percent_hack = no
allow_untrusted_routing (default: no)
Forward mail with sender-specified routing (user[@%!]remote[@%!]site)
from untrusted clients to destinations matching $relay_domains.
By default, this feature is turned off. This closes a nasty open
relay loophole where a backup MX host can be tricked into forwarding
junk mail to a primary MX host which then spams it out to the world.
This parameter also controls if non-local addresses with sender-specified
routing can match Postfix access tables. By default, such addresses
cannot match Postfix access tables, because the address is ambiguous.
alternate_config_directories (default: empty)
A list of non-default Postfix configuration directories that may
be specified with "-c config_directory" on the command line, or
via the MAIL_CONFIG environment parameter.
This list must be specified in the default Postfix configuration
directory, and is used by set-gid Postfix commands such as postqueue(1)
and postdrop(1).
always_bcc (default: empty)
Optional address that receives a "blind carbon copy" of each message
that is received by the Postfix mail system.
Note: if mail to the BCC address bounces it will be returned to
the sender.
Note: automatic BCC recipients are produced only for new mail.
To avoid mailer loops, automatic BCC recipients are not generated
for mail that Postfix forwards internally, nor for mail that Postfix
generates itself.
anvil_rate_time_unit (default: 60s)
The time unit over which client connection rates and other rates
are calculated.
This feature is implemented by the anvil(8) service which is not
part of the stable Postfix version 2.1 release.
The default interval is relatively short. Because of the high
frequency of updates, the anvil(8) server uses volatile memory
only. Thus, information is lost whenever the process terminates.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is s (seconds).
anvil_status_update_time (default: 600s)
How frequently the anvil(8) connection and rate limiting server
logs peak usage information.
This feature is available in Postfix 2.2 and later.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is s (seconds).
append_at_myorigin (default: yes)
With locally submitted mail, append the string "@$myorigin" to mail
addresses without domain information. With remotely submitted mail,
append the string "@$remote_header_rewrite_domain" instead.
Note 1: this feature is enabled by default and must not be turned off.
Postfix does not support domain-less addresses.
Note 2: with Postfix version 2.2, message header address rewriting
happens only when one of the following conditions is true:
*
The message is received with the Postfix sendmail(1) command,
*
The message is received from a network client that matches
$local_header_rewrite_clients,
*
The message is received from the network, and the
remote_header_rewrite_domain parameter specifies a non-empty value.
To get the behavior before Postfix version 2.2, specify
"local_header_rewrite_clients = static:all".
append_dot_mydomain (default: yes)
With locally submitted mail, append the string ".$mydomain" to
addresses that have no ".domain" information. With remotely submitted
mail, append the string ".$remote_header_rewrite_domain"
instead.
Note 1: this feature is enabled by default. If disabled, users will not be
able to send mail to "user@partialdomainname" but will have to
specify full domain names instead.
Note 2: with Postfix version 2.2, message header address rewriting
happens only when one of the following conditions is true:
*
The message is received with the Postfix sendmail(1) command,
*
The message is received from a network client that matches
$local_header_rewrite_clients,
*
The message is received from the network, and the
remote_header_rewrite_domain parameter specifies a non-empty value.
To get the behavior before Postfix version 2.2, specify
"local_header_rewrite_clients = static:all".
application_event_drain_time (default: 100s)
How long the postkick(1) command waits for a request to enter the
server's input buffer before giving up.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is s (seconds).
This feature is available in Postfix 2.1 and later.
authorized_flush_users (default: static:anyone)
List of users who are authorized to flush the queue.
By default, all users are allowed to flush the queue. Access is
always granted if the invoking user is the super-user or the
$mail_owner user. Otherwise, the real UID of the process is looked
up in the system password file, and access is granted only if the
corresponding login name is on the access list. The username
"unknown" is used for processes whose real UID is not found in the
password file.
Specify a list of user names, "/file/name" or "type:table" patterns,
separated by commas and/or whitespace. The list is matched left to
right, and the search stops on the first match. Specify "!name" to
exclude a name from the list. A "/file/name" pattern is replaced
by its contents; a "type:table" lookup table is matched when a name
matches a lookup key (the lookup result is ignored). Continue long
lines by starting the next line with whitespace.
This feature is available in Postfix 2.2 and later.
authorized_mailq_users (default: static:anyone)
List of users who are authorized to view the queue.
By default, all users are allowed to view the queue. Access is
always granted if the invoking user is the super-user or the
$mail_owner user. Otherwise, the real UID of the process is looked
up in the system password file, and access is granted only if the
corresponding login name is on the access list. The username
"unknown" is used for processes whose real UID is not found in the
password file.
Specify a list of user names, "/file/name" or "type:table" patterns,
separated by commas and/or whitespace. The list is matched left to
right, and the search stops on the first match. Specify "!name" to
exclude a name from the list. A "/file/name" pattern is replaced
by its contents; a "type:table" lookup table is matched when a name
matches a lookup key (the lookup result is ignored). Continue long
lines by starting the next line with whitespace.
This feature is available in Postfix 2.2 and later.
authorized_submit_users (default: static:anyone)
List of users who are authorized to submit mail with the sendmail(1)
command (and with the privileged postdrop(1) helper command).
By default, all users are allowed to submit mail. Otherwise, the
real UID of the process is looked up in the system password file,
and access is granted only if the corresponding login name is on
the access list. The username "unknown" is used for processes
whose real UID is not found in the password file. To deny mail
submission access to all users specify an empty list.
Specify a list of user names, "/file/name" or "type:table" patterns,
separated by commas and/or whitespace. The list is matched left to right,
and the search stops on the first match. Specify "!name" to exclude a
name from the list. A "/file/name" pattern is replaced by its contents;
a "type:table" lookup table is matched when a name matches a lookup key
(the lookup result is ignored). Continue long lines by starting the
next line with whitespace.
Example:
authorized_submit_users = !www, static:all
This feature is available in Postfix 2.2 and later.
authorized_verp_clients (default: $mynetworks)
What SMTP clients are allowed to specify the XVERP command.
This command requests that mail be delivered one recipient at a
time with a per recipient return address.
By default, only trusted clients are allowed to specify XVERP.
This parameter was introduced with Postfix version 1.1. Postfix
version 2.1 renamed this parameter to smtpd_authorized_verp_clients
and changed the default to none.
Specify a list of network/netmask patterns, separated by commas
and/or whitespace. The mask specifies the number of bits in the
network part of a host address. You can also specify hostnames or
\&.domain names (the initial dot causes the domain to match any name
below it), "/file/name" or "type:table" patterns. A "/file/name"
pattern is replaced by its contents; a "type:table" lookup table
is matched when a table entry matches a lookup string (the lookup
result is ignored). Continue long lines by starting the next line
with whitespace.
Note: IP version 6 address information must be specified inside
[] in the authorized_verp_clients value, and in files
specified with "/file/name". IP version 6 addresses contain the
":" character, and would otherwise be confused with a "type:table"
pattern.
Produce additional bounce(8) logfile records that can be read by
Postfix versions before 2.0. The current and more extensible "name =
value" format is needed in order to implement more sophisticated
functionality.
This feature is available in Postfix 2.1 and later.
The per-table I/O buffer size for programs that create Berkeley DB
hash or btree tables. Specify a byte count.
This feature is available in Postfix 2.0 and later.
berkeley_db_read_buffer_size (default: 131072)
The per-table I/O buffer size for programs that read Berkeley DB
hash or btree tables. Specify a byte count.
This feature is available in Postfix 2.0 and later.
best_mx_transport (default: empty)
Where the Postfix SMTP client should deliver mail when it detects
a "mail loops back to myself" error condition. This happens when
the local MTA is the best SMTP mail exchanger for a destination
not listed in $mydestination, $inet_interfaces, $proxy_interfaces,
$virtual_alias_domains, or $virtual_mailbox_domains. By default,
the Postfix SMTP client returns such mail as undeliverable.
Specify, for example, "best_mx_transport = local" to pass the mail
from the Postfix SMTP client to the local(8) delivery agent. You
can specify
any message delivery "transport" or "transport:nexthop" that is
defined in the master.cf file. See the transport(5) manual page
for the syntax and meaning of "transport" or "transport:nexthop".
However, this feature is expensive because it ties up a Postfix
SMTP client process while the local(8) delivery agent is doing its
work. It is more efficient (for Postfix) to list all hosted domains
in a table or database.
biff (default: yes)
Whether or not to use the local biff service. This service sends
"new mail" notifications to users who have requested new mail
notification with the UNIX command "biff y".
For compatibility reasons this feature is on by default. On systems
with lots of interactive users, the biff service can be a performance
drain. Specify "biff = no" in main.cf to disable.
body_checks (default: empty)
Optional lookup tables for content inspection as specified in
the body_checks(5) manual page.
Note: with Postfix versions before 2.0, these rules inspect
all content after the primary message headers.
body_checks_size_limit (default: 51200)
How much text in a message body segment (or attachment, if you
prefer to use that term) is subjected to body_checks inspection.
The amount of text is limited to avoid scanning huge attachments.
This feature is available in Postfix 2.0 and later.
bounce_notice_recipient (default: postmaster)
The recipient of postmaster notifications with the message headers
of mail that Postfix did not deliver and of SMTP conversation
transcripts of mail that Postfix did not receive. This feature is
enabled with the notify_classes parameter.
bounce_queue_lifetime (default: 5d)
The maximal time a bounce message is queued before it is considered
undeliverable. By default, this is the same as the queue life time
for regular mail.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is d (days).
Specify 0 when mail delivery should be tried only once.
This feature is available in Postfix 2.1 and later.
bounce_service_name (default: bounce)
The name of the bounce(8) service. This service maintains a record
of failed delivery attempts and generates non-delivery notifications.
This feature is available in Postfix 2.0 and later.
bounce_size_limit (default: 50000)
The maximal amount of original message text that is sent in a
non-delivery notification. Specify a byte count. If you increase
this limit, then you should increase the mime_nesting_limit value
proportionally.
bounce_template_file (default: empty)
Pathname of a configuration file with bounce message templates.
These override the built-in templates of delivery status notification
(DSN) messages for undeliverable mail, for delayed mail, successful
delivery, or delivery verification. The bounce(5) manual page
describes how to edit and test template files.
Template message body text may contain $name references to
Postfix configuration parameters. The result of $name expansion can
be previewed with "postconf -b file_name" before the file
is placed into the Postfix configuration directory.
This feature is available in Postfix 2.3 and later.
broken_sasl_auth_clients (default: no)
Enable inter-operability with SMTP clients that implement an obsolete
version of the AUTH command (RFC 2554). Examples of such clients
are MicroSoft Outlook Express version 4 and MicroSoft Exchange
version 5.0.
Specify "broken_sasl_auth_clients = yes" to have Postfix advertise
AUTH support in a non-standard way.
What addresses are subject to canonical_maps address mapping.
By default, canonical_maps address mapping is applied to envelope
sender and recipient addresses, and to header sender and header
recipient addresses.
Specify one or more of: envelope_sender, envelope_recipient,
header_sender, header_recipient
This feature is available in Postfix 2.2 and later.
canonical_maps (default: empty)
Optional address mapping lookup tables for message headers and
envelopes. The mapping is applied to both sender and recipient
addresses, in both envelopes and in headers, as controlled
with the canonical_classes parameter. This is typically used
to clean up dirty addresses from legacy mail systems, or to replace
login names by Firstname.Lastname. The table format and lookups
are documented in canonical(5). For an overview of Postfix address
manipulations see the ADDRESS_REWRITING_README document.
If you use this feature, run "postmap /etc/postfix/canonical" to
build the necessary DBM or DB file after every change. The changes
will become visible after a minute or so. Use "postfix reload"
to eliminate the delay.
Note: with Postfix version 2.2, message header address mapping
happens only when message header address rewriting is enabled:
*
The message is received with the Postfix sendmail(1) command,
*
The message is received from a network client that matches
$local_header_rewrite_clients,
*
The message is received from the network, and the
remote_header_rewrite_domain parameter specifies a non-empty value.
To get the behavior before Postfix version 2.2, specify
"local_header_rewrite_clients = static:all".
The name of the cleanup(8) service. This service rewrites addresses
into the standard form, and performs canonical(5) address mapping
and virtual(5) aliasing.
This feature is available in Postfix 2.0 and later.
command_directory (default: see postconf -d output)
The location of all postfix administrative commands.
command_execution_directory (default: empty)
The local(8) delivery agent working directory for delivery to
external command. Failure to change directory causes the delivery
to be deferred.
The following $name expansions are done on command_execution_directory
before the directory is changed. Expansion happens in the context
of the delivery request. The result of $name expansion is filtered
with the character set that is specified with the
execution_directory_expansion_filter parameter.
$user
The recipient's username.
$shell
The recipient's login shell pathname.
$home
The recipient's home directory.
$recipient
The full recipient address.
$extension
The optional recipient address extension.
$domain
The recipient domain.
$local
The entire recipient localpart.
$recipient_delimiter
The system-wide recipient address extension delimiter.
${name?value}
Expands to value when $name is non-empty.
${name:value}
Expands to value when $name is empty.
Instead of $name you can also specify ${name} or $(name).
This feature is available in Postfix 2.2 and later.
command_expansion_filter (default: see postconf -d output)
Restrict the characters that the local(8) delivery agent allows in
$name expansions of $mailbox_command. Characters outside the
allowed set are replaced by underscores.
command_time_limit (default: 1000s)
Time limit for delivery to external commands. This limit is used
by the local(8) delivery agent, and is the default time limit for
delivery by the pipe(8) delivery agent.
Note: if you set this time limit to a large value you must update the
global ipc_timeout parameter as well.
config_directory (default: see postconf -d output)
The default location of the Postfix main.cf and master.cf
configuration files. This can be overruled via the following
mechanisms:
*
The MAIL_CONFIG environment variable (daemon processes
and commands).
*
The "-c" command-line option (commands only).
With Postfix command that run with set-gid privileges, a
config_directory override requires either root privileges, or it
requires that the directory is listed with the alternate_config_directories
parameter in the default main.cf file.
connection_cache_protocol_timeout (default: 5s)
Time limit for connection cache connect, send or receive
operations. The time limit is enforced in the client.
This feature is available in Postfix 2.3 and later.
connection_cache_service (default: scache)
The name of the scache(8) connection cache service. This service
maintains a limited pool of cached sessions.
How frequently the scache(8) server logs usage statistics with
connection cache hit and miss rates for logical destinations and for
physical endpoints.
connection_cache_ttl_limit (default: 2s)
The maximal time-to-live value that the scache(8) connection
cache server
allows. Requests that specify a larger TTL will be stored with the
maximum allowed TTL. The purpose of this additional control is to
protect the infrastructure against careless people. The cache TTL
is already bounded by $max_idle.
content_filter (default: empty)
The name of a mail delivery transport that filters mail after
it is queued.
This parameter uses the same syntax as the right-hand side of a
Postfix transport(5) table. This setting has a lower precedence
than a content filter that is specified with an access(5) table or
in a header_checks(5) or body_checks(5) table.
daemon_directory (default: see postconf -d output)
The directory with Postfix support programs and daemon programs.
These should not be invoked directly by humans. The directory must
be owned by root.
daemon_timeout (default: 18000s)
How much time a Postfix daemon process may take to handle a
request before it is terminated by a built-in watchdog timer.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is s (seconds).
debug_peer_level (default: 2)
The increment in verbose logging level when a remote client or
server matches a pattern in the debug_peer_list parameter.
debug_peer_list (default: empty)
Optional list of remote client or server hostname or network
address patterns that cause the verbose logging level to increase
by the amount specified in $debug_peer_level.
Specify domain names, network/netmask patterns, "/file/name"
patterns or "type:table" lookup tables. The right-hand side result
from "type:table" lookups is ignored.
Pattern matching of domain names is controlled by the
parent_domain_matches_subdomains parameter.
The external command to execute when a Postfix daemon program is
invoked with the -D option.
Use "command .. & sleep 5" so that the debugger can attach before
the process marches on. If you use an X-based debugger, be sure to
set up your XAUTHORITY environment variable before starting Postfix.
default_database_type (default: see postconf -d output)
The default database type for use in newaliases(1), postalias(1)
and postmap(1) commands. On many UNIX systems the default type is
either dbm or hash. The default setting is frozen
when the Postfix system is built.
How often the Postfix queue manager's scheduler is allowed to
preempt delivery of one message with another.
Each transport maintains a so-called "available delivery slot counter"
for each message. One message can be preempted by another one when
the other message can be delivered using no more delivery slots
(i.e., invocations of delivery agents) than the current message
counter has accumulated (or will eventually accumulate - see about
slot loans below). This parameter controls how often is the counter
incremented - it happens after each default_delivery_slot_cost
recipients have been delivered.
The cost of 0 is used to disable the preempting scheduling completely.
The minimum value the scheduling algorithm can use is 2 - use it
if you want to maximize the message throughput rate. Although there
is no maximum, it doesn't make much sense to use values above say
50.
The only reason why the value of 2 is not the default is the way
this parameter affects the delivery of mailing-list mail. In the
worst case, their delivery can take somewhere between (cost+1/cost)
and (cost/cost-1) times more than if the preemptive scheduler was
disabled. The default value of 5 turns out to provide reasonable
message response times while making sure the mailing-list deliveries
are not extended by more than 20-25 percent even in the worst case.
The default value for transport-specific _delivery_slot_discount
settings.
This parameter speeds up the moment when a message preemption can
happen. Instead of waiting until the full amount of delivery slots
required is available, the preemption can happen when
transport_delivery_slot_discount percent of the required amount
plus transport_delivery_slot_loan still remains to be accumulated.
Note that the full amount will still have to be accumulated before
another preemption can take place later.
default_delivery_slot_loan (default: 3)
The default value for transport-specific _delivery_slot_loan
settings.
This parameter speeds up the moment when a message preemption can
happen. Instead of waiting until the full amount of delivery slots
required is available, the preemption can happen when
transport_delivery_slot_discount percent of the required amount
plus transport_delivery_slot_loan still remains to be accumulated.
Note that the full amount will still have to be accumulated before
another preemption can take place later.
The default maximal number of parallel deliveries to the same
destination. This is the default limit for delivery via the lmtp(8),
pipe(8), smtp(8) and virtual(8) delivery agents.
default_destination_recipient_limit (default: 50)
The default maximal number of recipients per message delivery.
This is the default limit for delivery via the lmtp(8), pipe(8),
smtp(8) and virtual(8) delivery agents.
Setting this parameter to a value of 1 changes the meaning of
the corresponding per-destination concurrency limit from concurrency
per domain into concurrency per recipient.
default_extra_recipient_limit (default: 1000)
The default value for the extra per-transport limit imposed on the
number of in-memory recipients. This extra recipient space is
reserved for the cases when the Postfix queue manager's scheduler
preempts one message with another and suddenly needs some extra
recipients slots for the chosen message in order to avoid performance
degradation.
default_minimum_delivery_slots (default: 3)
How many recipients a message must have in order to invoke the
Postfix queue manager's scheduling algorithm at all. Messages
which would never accumulate at least this many delivery slots
(subject to slot cost parameter as well) are never preempted.
default_privs (default: nobody)
The default rights used by the local(8) delivery agent for delivery
to external file or command. These rights are used when delivery
is requested from an aliases(5) file that is owned by root, or
when delivery is done on behalf of root. DO NOT SPECIFY A
PRIVILEGED USER OR THE POSTFIX OWNER.
default_process_limit (default: 100)
The default maximal number of Postfix child processes that provide
a given service. This limit can be overruled for specific services
in the master.cf file.
default_rbl_reply (default: see postconf -d output)
The default SMTP server response template for a request that is
rejected by an RBL-based restriction. This template can be overruled
by specific entries in the optional rbl_reply_maps lookup table.
This feature is available in Postfix 2.0 and later.
The template is subject to exactly one level of $name substitution:
$client
The client hostname and IP address, formatted as name[address].
$client_address
The client IP address.
$client_name
The client hostname or "unknown". See reject_unknown_client_hostname
for more details.
$reverse_client_name
The client hostname from address->name lookup, or "unknown".
See reject_unknown_reverse_client_hostname for more details.
$helo_name
The hostname given in HELO or EHLO command or empty string.
$rbl_class
The blacklisted entity type: Client host, Helo command, Sender
address, or Recipient address.
$rbl_code
The numerical SMTP response code, as specified with the
maps_rbl_reject_code configuration parameter. Note: The numerical
SMTP response code is required, and must appear at the start of the
reply. With Postfix version 2.3 and later this information may be followed
by an RFC 3463 enhanced status code.
$rbl_domain
The RBL domain where $rbl_what is blacklisted.
$rbl_reason
The reason why $rbl_what is blacklisted, or an empty string.
$rbl_what
The entity that is blacklisted (an IP address, a hostname, a domain
name, or an email address whose domain was blacklisted).
$recipient
The recipient address or <> in case of the null address.
$recipient_domain
The recipient domain or empty string.
$recipient_name
The recipient address localpart or <> in case of null address.
$sender
The sender address or <> in case of the null address.
$sender_domain
The sender domain or empty string.
$sender_name
The sender address localpart or <> in case of the null address.
${name?text}
Expands to `text' if $name is not empty.
${name:text}
Expands to `text' if $name is empty.
Instead of $name you can also specify ${name} or $(name).
Note: when an enhanced status code is specified in an RBL reply
template, it is subject to modification. The following transformations
are needed when the same RBL reply template is used for client,
helo, sender, or recipient access restrictions.
*
When rejecting a sender address, the Postfix SMTP server
will transform a recipient DSN status (e.g., 4.1.1-4.1.6) into the
corresponding sender DSN status, and vice versa.
*
When rejecting non-address information (such as the HELO
command argument or the client hostname/address), the Postfix SMTP
server will transform a sender or recipient DSN status into a generic
non-address DSN status (e.g., 4.0.0).
default_recipient_limit (default: 10000)
The default per-transport upper limit on the number of in-memory
recipients. These limits take priority over the global
qmgr_message_recipient_limit after the message has been assigned
to the respective transports. See also default_extra_recipient_limit
and qmgr_message_recipient_minimum.
default_transport (default: smtp)
The default mail delivery transport and next-hop destination for
destinations that do not match $mydestination, $inet_interfaces,
$proxy_interfaces, $virtual_alias_domains, $virtual_mailbox_domains,
or $relay_domains. In order of decreasing precedence, the nexthop
destination is taken from $default_transport,
$sender_dependent_relayhost_maps, $relayhost, or from the recipient
domain. This information can be overruled with the transport(5)
table.
Specify a string of the form transport:nexthop, where transport
is the name of a mail delivery transport defined in master.cf.
The :nexthop part is optional. For more details see the
transport(5) manual page.
Example:
default_transport = uucp:relayhostname
default_verp_delimiters (default: +=)
The two default VERP delimiter characters. These are used when
no explicit delimiters are specified with the SMTP XVERP command
or with the "sendmail -V" command-line option. Specify
characters that are allowed by the verp_delimiter_filter setting.
This feature is available in Postfix 1.1 and later.
defer_code (default: 450)
The numerical Postfix SMTP server response code when a remote SMTP
client request is rejected by the "defer" restriction.
Do not change this unless you have a complete understanding of RFC 821.
defer_service_name (default: defer)
The name of the defer service. This service is implemented by the
bounce(8) daemon and maintains a record
of failed delivery attempts and generates non-delivery notifications.
This feature is available in Postfix 2.0 and later.
defer_transports (default: empty)
The names of message delivery transports that should not deliver mail
unless someone issues "sendmail -q" or equivalent. Specify zero
or more names of mail delivery transports names that appear in the
first field of master.cf.
Example:
defer_transports = smtp
delay_logging_resolution_limit (default: 2)
The maximal number of digits after the decimal point when logging
sub-second delay values. Specify a number in the range 0..6.
Large delay values are rounded off to an integral number seconds;
delay values below the delay_logging_resolution_limit are logged
as "0", and small delay values are logged with at most two-digit
precision.
The format of the "delays=a/b/c/d" logging is as follows:
*
a = time before the queue manager, including message transmission
*
b = time in queue manager
*
c = time in connection setup, including DNS, EHLO and TLS
*
d = time in message transmission
This feature is available in Postfix 2.3 and later.
delay_notice_recipient (default: postmaster)
The recipient of postmaster notifications with the message headers
of mail that cannot be delivered within $delay_warning_time time
units.
This feature is enabled with the delay_warning_time parameter.
delay_warning_time (default: 0h)
The time after which the sender receives the message headers of
mail that is still queued.
To enable this feature, specify a non-zero time value (an integral
value plus an optional one-letter suffix that specifies the time
unit).
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is h (hours).
deliver_lock_attempts (default: 20)
The maximal number of attempts to acquire an exclusive lock on a
mailbox file or bounce(8) logfile.
deliver_lock_delay (default: 1s)
The time between attempts to acquire an exclusive lock on a mailbox
file or bounce(8) logfile.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is s (seconds).
disable_dns_lookups (default: no)
Disable DNS lookups in the Postfix SMTP and LMTP clients. When
disabled, hosts are looked up with the gethostbyname() system
library routine which normally also looks in /etc/hosts.
DNS lookups are enabled by default.
disable_mime_input_processing (default: no)
Turn off MIME processing while receiving mail. This means that no
special treatment is given to Content-Type: message headers, and
that all text after the initial message headers is considered to
be part of the message body.
This feature is available in Postfix 2.0 and later.
Mime input processing is enabled by default, and is needed in order
to recognize MIME headers in message content.
disable_mime_output_conversion (default: no)
Disable the conversion of 8BITMIME format to 7BIT format. Mime
output conversion is needed when the destination does not advertise
8BITMIME support.
This feature is available in Postfix 2.0 and later.
disable_verp_bounces (default: no)
Disable sending one bounce report per recipient.
The default, one per recipient, is what ezmlm needs.
This feature is available in Postfix 1.1 and later.
disable_vrfy_command (default: no)
Disable the SMTP VRFY command. This stops some techniques used to
harvest email addresses.
Example:
disable_vrfy_command = no
dont_remove (default: 0)
Don't remove queue files and save them to the "saved" mail queue.
This is a debugging aid. To inspect the envelope information and
content of a Postfix queue file, use the postcat(1) command.
double_bounce_sender (default: double-bounce)
The sender address of postmaster notifications that are generated
by the mail system. All mail to this address is silently discarded,
in order to terminate mail bounce loops.
duplicate_filter_limit (default: 1000)
The maximal number of addresses remembered by the address
duplicate filter for aliases(5) or virtual(5) alias expansion, or
for showq(8) queue displays.
empty_address_recipient (default: MAILER-DAEMON)
The recipient of mail addressed to the null address. Postfix does
not accept such addresses in SMTP commands, but they may still be
created locally as the result of configuration or software error.
enable_errors_to (default: no)
Report mail delivery errors to the address specified with the
non-standard Errors-To: message header, instead of the envelope
sender address (this feature is removed with Postfix version 2.2, is
turned off by default with Postfix version 2.1, and is always turned on
with older Postfix versions).
enable_original_recipient (default: yes)
Enable support for the X-Original-To message header. This header
is needed for multi-recipient mailboxes.
When this parameter is set to yes, the cleanup(8) daemon performs
duplicate elimination on distinct pairs of (original recipient,
rewritten recipient), and generates non-empty original recipient
queue file records.
When this parameter is set to no, the cleanup(8) daemon performs
duplicate elimination on the rewritten recipient address only, and
generates empty original recipient queue file records.
This feature is available in Postfix 2.1 and later. With Postfix
version 2.0, support for the X-Original-To message header is always turned
on. Postfix versions before 2.0 have no support for the X-Original-To
message header.
error_notice_recipient (default: postmaster)
The recipient of postmaster notifications about mail delivery
problems that are caused by policy, resource, software or protocol
errors. These notifications are enabled with the notify_classes
parameter.
error_service_name (default: error)
The name of the error(8) pseudo delivery agent. This service always
returns mail as undeliverable.
This feature is available in Postfix 2.0 and later.
execution_directory_expansion_filter (default: see postconf -d output)
Restrict the characters that the local(8) delivery agent allows
in $name expansions of $command_execution_directory. Characters
outside the allowed set are replaced by underscores.
This feature is available in Postfix 2.2 and later.
expand_owner_alias (default: no)
When delivering to an alias "aliasname" that has an "owner-aliasname"
companion alias, set the envelope sender address to the expansion
of the "owner-aliasname" alias. Normally, Postfix sets the envelope
sender address to the name of the "owner-aliasname" alias.
export_environment (default: see postconf -d output)
The list of environment variables that a Postfix process will export
to non-Postfix processes. The TZ variable is needed for sane
time keeping on System-V-ish systems.
Specify a list of names and/or name=value pairs, separated by
whitespace or comma. The name=value form is supported with
Postfix version 2.1 and later.
Example:
export_environment = TZ PATH=/bin:/usr/bin
extract_recipient_limit (default: 10240)
The maximal number of recipient addresses that Postfix will extract
from message headers when mail is submitted with "sendmail -t".
This feature was removed in Postfix version 2.1.
fallback_relay (default: empty)
Optional list of relay hosts for SMTP destinations that can't be
found or that are unreachable. With Postfix 2.3 this parameter
is renamed to smtp_fallback_relay.
By default, mail is returned to the sender when a destination is
not found, and delivery is deferred when a destination is unreachable.
The fallback relays must be SMTP destinations. Specify a domain,
host, host:port, [host]:port, [address] or [address]:port; the form
[host] turns off MX lookups. If you specify multiple SMTP
destinations, Postfix will try them in the specified order.
Note: before Postfix 2.2, do not use the fallback_relay feature
when relaying mail
for a backup or primary MX domain. Mail would loop between the
Postfix MX host and the fallback_relay host when the final destination
is unavailable.
*
In main.cf specify "relay_transport = relay",
*
In master.cf specify "-o fallback_relay =" (i.e., empty) at
the end of the relay entry.
*
In transport maps, specify "relay:nexthop..."
as the right-hand side for backup or primary MX domain entries.
Postfix version 2.2 and later will not use the fallback_relay feature
for destinations that it is MX host for.
fallback_transport (default: empty)
Optional message delivery transport that the local(8) delivery
agent should use for names that are not found in the aliases(5)
or UNIX password database.
The precedence of local(8) delivery features from high to low
is: aliases, .forward files, mailbox_transport_maps, mailbox_transport,
mailbox_command_maps, mailbox_command, home_mailbox, mail_spool_directory,
fallback_transport_maps, fallback_transport and luser_relay.
fallback_transport_maps (default: empty)
Optional lookup tables with per-recipient message delivery
transports for recipients that the local(8) delivery agent could
not find in the aliases(5) or UNIX password database.
The precedence of local(8) delivery features from high to low
is: aliases, .forward files, mailbox_transport_maps, mailbox_transport,
mailbox_command_maps, mailbox_command, home_mailbox, mail_spool_directory,
fallback_transport_maps, fallback_transport and luser_relay.
For safety reasons, this feature does not allow $number
substitutions in regular expression maps.
This feature is available in Postfix 2.3 and later.
fast_flush_domains (default: $relay_domains)
Optional list of destinations that are eligible for per-destination
logfiles with mail that is queued to those destinations.
By default, Postfix maintains "fast flush" logfiles only for
destinations that the Postfix SMTP server is willing to relay to
(i.e. the default is: "fast_flush_domains = $relay_domains"; see
the relay_domains parameter in the postconf(5) manual).
Specify a list of hosts or domains, "/file/name" patterns or
"type:table" lookup tables, separated by commas and/or whitespace.
Continue long lines by starting the next line with whitespace. A
"/file/name" pattern is replaced by its contents; a "type:table"
lookup table is matched when the domain or its parent domain appears
as lookup key.
Specify "fast_flush_domains =" (i.e., empty) to disable the feature
altogether.
fast_flush_purge_time (default: 7d)
The time after which an empty per-destination "fast flush" logfile
is deleted.
You can specify the time as a number, or as a number followed by
a letter that indicates the time unit: s=seconds, m=minutes, h=hours,
d=days, w=weeks. The default time unit is days.
fast_flush_refresh_time (default: 12h)
The time after which a non-empty but unread per-destination "fast
flush" logfile needs to be refreshed. The contents of a logfile
are refreshed by requesting delivery of all messages listed in the
logfile.
You can specify the time as a number, or as a number followed by
a letter that indicates the time unit: s=seconds, m=minutes, h=hours,
d=days, w=weeks. The default time unit is hours.
fault_injection_code (default: 0)
Force specific internal tests to fail, to test the handling of
errors that are difficult to reproduce otherwise.
flush_service_name (default: flush)
The name of the flush(8) service. This service maintains per-destination
logfiles with the queue file names of mail that is queued for those
destinations.
This feature is available in Postfix 2.0 and later.
fork_attempts (default: 5)
The maximal number of attempts to fork() a child process.
fork_delay (default: 1s)
The delay between attempts to fork() a child process.
Time units: s (seconds), m (minutes), h (hours), d (days), w
(weeks). The default time unit is s (seconds).
forward_expansion_filter (default: see postconf -d output)
Restrict the characters that the local(8) delivery agent allows in
$name expansions of $forward_path. Characters outside the
allowed set are replaced by underscores.
forward_path (default: see postconf -d output)
The local(8) delivery agent search list for finding a .forward
file with user-specified delivery methods. The first file that is
found is used.
The following $name expansions are done on forward_path before
the search actually happens. The result of $name expansion is
filtered with the character set that is specified with the
forward_expansion_filter parameter.
$user
The recipient's username.
$shell
The recipient's login shell pathname.
$home
The recipient's home directory.
$recipient
The full recipient address.
$extension
The optional recipient address extension.
$domain
The recipient domain.
$local
The entire recipient localpart.
$recipient_delimiter
The system-wide recipient address extension delimiter.
${name?value}
Expands to value when $name is non-empty.
${name:value}
Expands to value when $name is empty.
Instead of $name you can also specify ${name} or $(name).
Update the local(8) delivery agent's idea of the Delivered-To:
address (see prepend_delivered_header) only once, at the start of
a delivery attempt; do not update the Delivered-To: address while
expanding aliases or .forward files.
This feature is available in Postfix 2.3 and later. With older
Postfix releases, the behavior is as if this parameter is set to
"no". The old setting can be expensive with deeply nested aliases
or .forward files. When an alias or .forward file changes the
Delivered-To: address, it ties up one queue file and one cleanup
process instance while mail is being forwarded.
hash_queue_depth (default: 1)
The number of subdirectory levels for queue directories listed with
the hash_queue_names parameter.
After changing the hash_queue_names or hash_queue_depth parameter,
execute the command "postfix reload".
hash_queue_names (default: deferred, defer)
The names of queue directories that are split across multiple
subdirectory levels.
Before Postfix version 2.2, the default list of hashed queues
was significantly larger. Claims about improvements in file system
technology suggest that hashing of the incoming and active queues
is no longer needed. Fewer hashed directories speed up the time
needed to restart Postfix.
After changing the hash_queue_names or hash_queue_depth parameter,
execute the command "postfix reload".
header_address_token_limit (default: 10240)
The maximal number of address tokens are allowed in an address
message header. Information that exceeds the limit is discarded.
The limit is enforced by the cleanup(8) server.
header_checks (default: empty)
Optional lookup tables for content inspection of primary non-MIME
message headers, as specified in the header_checks(5) manual page.
header_size_limit (default: 102400)
The maximal amount of memory in bytes for storing a message header.
If a header is larger, the excess is discarded. The limit is
enforced by the cleanup(8) server.
helpful_warnings (default: yes)
Log warnings about problematic configuration settings, and provide
helpful suggestions.
This feature is available in Postfix 2.0 and later.
home_mailbox (default: empty)
Optional pathname of a mailbox file relative to a local(8) user's
home directory.
Specify a pathname ending in "/" for qmail-style delivery.
The precedence of local(8) delivery features from high to low
is: aliases, .forward files, mailbox_transport_maps, mailbox_transport,
mailbox_command_maps, mailbox_command, home_mailbox, mail_spool_directory,
fallback_transport_maps, fallback_transport and luser_relay.
Examples:
home_mailbox = Mailbox
home_mailbox = Maildir/
hopcount_limit (default: 50)
The maximal number of Received: message headers that is allowed
in the primary message headers. A message that exceeds the limit
is bounced, in order to stop a mailer loop.
html_directory (default: see postconf -d output)
The location of Postfix HTML files that describe how to build,
configure or operate a specific Postfix subsystem or feature.
ignore_mx_lookup_error (default: no)
Ignore DNS MX lookups that produce no response. By default,
the Postfix SMTP client defers delivery and tries again after some
delay. This behavior is required by the SMTP standard.
Specify "ignore_mx_lookup_error = yes" to force a DNS A record
lookup instead. This violates the SMTP standard and can result in
mis-delivery of mail.
import_environment (default: see postconf -d output)
The list of environment parameters that a Postfix process will
import from a non-Postfix parent process. Examples of relevant
parameters:
TZ
Needed for sane time keeping on most System-V-ish systems.
DISPLAY
Needed for debugging Postfix daemons with an X-windows debugger.
XAUTHORITY
Needed for debugging Postfix daemons with an X-windows debugger.
MAIL_CONFIG
Needed to make "postfix -c" work.
Specify a list of names and/or name=value pairs, separated by
whitespace or comma. The name=value form is supported with
Postfix version 2.1 and later.
in_flow_delay (default: 1s)
Time to pause before accepting a new message, when the message
arrival rate exceeds the message delivery rate. This feature is
turned on by default (it's disabled on SCO UNIX due to an SCO bug).
With the default 100 SMTP server process limit, "in_flow_delay
= 1s" limits the mail inflow to 100 messages per second above the
number of messages delivered per second.
Specify 0 to disable the feature. Valid delays are 0..10.
inet_interfaces (default: all)
The network interface addresses that this mail system receives
mail on. Specify "all" to receive mail on all network
interfaces (default), and "loopback-only" to receive mail
on loopback network interfaces only (Postfix version 2.2 and later). The
parameter also controls delivery of mail to user@[ip.address].
Note 1: you need to stop and start Postfix when this parameter changes.
Note 2: address information may be enclosed inside [],
but this form is not recommended here.
When inet_interfaces specifies just one IPv4 and/or IPv6 address
that is not a loopback address, the Postfix SMTP client will use
this address as the IP source address for outbound mail. Support
for IPv6 is available in Postfix version 2.2 and later.
On a multi-homed firewall with separate Postfix instances listening on the
"inside" and "outside" interfaces, this can prevent each instance from
being able to reach servers on the "other side" of the firewall. Setting
smtp_bind_address to 0.0.0.0 avoids the potential problem for
IPv4, and setting smtp_bind_address6 to :: solves the problem
for IPv6.
A better solution for multi-homed firewalls is to leave inet_interfaces
at the default value and instead use explicit IP addresses in
the master.cf SMTP server definitions. This preserves the Postfix
SMTP client's
loop detection, by ensuring that each side of the firewall knows that the
other IP address is still the same host. Setting $inet_interfaces to a
single IPv4 and/or IPV6 address is primarily useful with virtual
hosting of domains on
secondary IP addresses, when each IP address serves a different domain
(and has a different $myhostname setting).
See also the proxy_interfaces parameter, for network addresses that
are forwarded to Postfix by way of a proxy or address translator.
Examples:
inet_interfaces = all (DEFAULT)
inet_interfaces = loopback-only (Postfix version 2.2 and later)
inet_interfaces = 127.0.0.1
inet_interfaces = 127.0.0.1, [::1] (Postfix version 2.2 and later)
inet_interfaces = 192.168.1.2, 127.0.0.1
inet_protocols (default: ipv4)
The Internet protocols Postfix will attempt to use when making
or accepting connections. Specify one or more of "ipv4"
or "ipv6", separated by whitespace or commas. The form
"all" is equivalent to "ipv4, ipv6" or "ipv4", depending
on whether the operating system implements IPv6.
This feature is available in Postfix 2.2 and later.
Note: you MUST stop and start Postfix after changing this
parameter.
On systems that pre-date IPV6_V6ONLY support (RFC 3493), an
IPv6 server will also accept IPv4 connections, even when IPv4 is
turned off with the inet_protocols parameter. On systems with
IPV6_V6ONLY support, Postfix will use separate server sockets for
IPv6 and IPv4, and each will accept only connections for the
corresponding protocol.
When IPv4 support is enabled via the inet_protocols parameter,
Postfix will to DNS type A record lookups, and will convert
IPv4-in-IPv6 client IP addresses (::ffff:1.2.3.4) to their original
IPv4 form (1.2.3.4). The latter is needed on hosts that pre-date
IPV6_V6ONLY support (RFC 3493).
When IPv6 support is enabled via the inet_protocols parameter,
Postfix will do DNS type AAAA record lookups.
When both IPv4 and IPv6 support are enabled, the Postfix SMTP
client will attempt to connect via IPv6 before attempting to use
IPv4.
The initial per-destination concurrency level for parallel delivery
to the same destination. This limit applies to delivery via smtp(8),
and via the pipe(8) and virtual(8) delivery agents.
Warning: with concurrency of 1, one bad message can be enough to
block all mail to a site.
internal_mail_filter_classes (default: empty)
What categories of Postfix-generated mail are subject to
before-queue content inspection by non_smtpd_milters, header_checks
and body_checks. Specify zero or more of the following, separated
by whitespace or comma.
bounce
Inspect the content of delivery
status notifications.
notify
Inspect the content of postmaster
notifications by the smtp(8) and smtpd(8) processes.
NOTE: It's generally not safe to enable content inspection of
Postfix-generated email messages. The user is warned.
This feature is available in Postfix 2.3 and later.
invalid_hostname_reject_code (default: 501)
The numerical Postfix SMTP server response code when the client
HELO or EHLO command parameter is rejected by the reject_invalid_helo_hostname
restriction.
Do not change this unless you have a complete understanding of RFC 821.
ipc_idle (default: 100s)
The time after which a client closes an idle internal communication
channel. The purpose is to allow servers to terminate voluntarily
after they become idle. This is used, for example, by the address
resolving and rewriting clients.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is s (seconds).
ipc_timeout (default: 3600s)
The time limit for sending or receiving information over an internal
communication channel. The purpose is to break out of deadlock
situations. If the time limit is exceeded the software aborts with a
fatal error.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is s (seconds).
ipc_ttl (default: 1000s)
The time after which a client closes an active internal communication
channel. The purpose is to allow servers to terminate voluntarily
after reaching their client limit. This is used, for example, by
the address resolving and rewriting clients.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is s (seconds).
This feature is available in Postfix 2.1 and later.
line_length_limit (default: 2048)
Upon input, long lines are chopped up into pieces of at most
this length; upon delivery, long lines are reconstructed.
lmtp_bind_address (default: empty)
The LMTP-specific version of the smtp_bind_address configuration
parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_bind_address6 (default: empty)
The LMTP-specific version of the smtp_bind_address6 configuration
parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_cache_connection (default: yes)
Keep Postfix LMTP client connections open for up to $max_idle
seconds. When the LMTP client receives a request for the same
connection the connection is reused.
The effectiveness of cached connections will be determined by the
number of LMTP servers in use, and the concurrency limit specified
for the LMTP client. Cached connections are closed under any of
the following conditions:
*
The LMTP client idle time limit is reached. This limit is
specified with the Postfix max_idle configuration parameter.
*
A delivery request specifies a different destination than the
one currently cached.
*
The per-process limit on the number of delivery requests is
reached. This limit is specified with the Postfix max_use
configuration parameter.
*
Upon the onset of another delivery request, the LMTP server
associated with the current session does not respond to the RSET
command.
Most of these limitations will be removed after Postfix implements
a connection cache that is shared among multiple LMTP client
programs.
lmtp_cname_overrides_servername (default: yes)
The LMTP-specific version of the smtp_cname_overrides_servername
configuration parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_connect_timeout (default: 0s)
The LMTP client time limit for completing a TCP connection, or
zero (use the operating system built-in time limit). When no
connection can be made within the deadline, the LMTP client tries
the next address on the mail exchanger list.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is s (seconds).
The LMTP-specific version of the smtp_connection_cache_destinations
configuration parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_connection_cache_on_demand (default: yes)
The LMTP-specific version of the smtp_connection_cache_on_demand
configuration parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_connection_cache_time_limit (default: 2s)
The LMTP-specific version of the
smtp_connection_cache_time_limit configuration parameter.
See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_connection_reuse_time_limit (default: 300s)
The LMTP-specific version of the smtp_connection_reuse_time_limit
configuration parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_data_done_timeout (default: 600s)
The LMTP client time limit for sending the LMTP ".", and for
receiving the server response. When no response is received within
the deadline, a warning is logged that the mail may be delivered
multiple times.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is s (seconds).
lmtp_data_init_timeout (default: 120s)
The LMTP client time limit for sending the LMTP DATA command, and
for receiving the server response.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is s (seconds).
lmtp_data_xfer_timeout (default: 180s)
The LMTP client time limit for sending the LMTP message content.
When the connection stalls for more than $lmtp_data_xfer_timeout
the LMTP client terminates the transfer.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is s (seconds).
lmtp_defer_if_no_mx_address_found (default: no)
The LMTP-specific version of the smtp_defer_if_no_mx_address_found
configuration parameter. See there for details.
This feature is available in Postfix 2.3 and later.
The maximal number of parallel deliveries to the same destination
via the lmtp message delivery transport. This limit is enforced by
the queue manager. The message delivery transport name is the first
field in the entry in the master.cf file.
The maximal number of recipients per delivery via the lmtp
message delivery transport. This limit is enforced by the queue
manager. The message delivery transport name is the first field in
the entry in the master.cf file.
Setting this parameter to a value of 1 changes the meaning of
lmtp_destination_concurrency_limit from concurrency per domain into
concurrency per recipient.
Lookup tables, indexed by the remote LMTP server address, with
case insensitive lists of LHLO keywords (pipelining, starttls,
auth, etc.) that the LMTP client will ignore in the LHLO response
from a remote LMTP server. See lmtp_discard_lhlo_keywords for
details. The table is not indexed by hostname for consistency with
smtpd_discard_ehlo_keyword_address_maps.
This feature is available in Postfix 2.3 and later.
lmtp_discard_lhlo_keywords (default: $myhostname)
A case insensitive list of LHLO keywords (pipelining, starttls,
auth, etc.) that the LMTP client will ignore in the LHLO response
from a remote LMTP server.
This feature is available in Postfix 2.3 and later.
Notes:
*
Specify the silent-discard pseudo keyword to prevent
this action from being logged.
*
Use the lmtp_discard_lhlo_keyword_address_maps feature to
discard LHLO keywords selectively.
lmtp_enforce_tls (default: no)
The LMTP-specific version of the smtp_enforce_tls configuration
parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_generic_maps (default: empty)
The LMTP-specific version of the smtp_generic_maps configuration
parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_host_lookup (default: dns)
The LMTP-specific version of the smtp_host_lookup configuration
parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_lhlo_name (default: $myhostname)
The hostname to send in the LMTP LHLO command.
The default value is the machine hostname. Specify a hostname or
[ip.add.re.ss].
This information can be specified in the main.cf file for all LMTP
clients, or it can be specified in the master.cf file for a specific
client, for example:
The LMTP-specific version of the smtp_pix_workaround_threshold_time
configuration parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_quit_timeout (default: 300s)
The LMTP client time limit for sending the QUIT command, and for
receiving the server response.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is s (seconds).
lmtp_quote_rfc821_envelope (default: yes)
The LMTP-specific version of the smtp_quote_rfc821_envelope
configuration parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_randomize_addresses (default: yes)
The LMTP-specific version of the smtp_randomize_addresses
configuration parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_rcpt_timeout (default: 300s)
The LMTP client time limit for sending the RCPT TO command, and
for receiving the server response.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is s (seconds).
lmtp_rset_timeout (default: 20s)
The LMTP client time limit for sending the RSET command, and
for receiving the server response. The LMTP client sends RSET in
order to finish a recipient address probe, or to verify that a
cached connection is still alive.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is s (seconds).
lmtp_sasl_auth_enable (default: no)
Enable SASL authentication in the Postfix LMTP client.
lmtp_sasl_mechanism_filter (default: empty)
The LMTP-specific version of the smtp_sasl_mechanism_filter
configuration parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_sasl_password_maps (default: empty)
Optional LMTP client lookup tables with one username:password entry
per host or domain. If a remote host or domain has no username:password
entry, then the Postfix LMTP client will not attempt to authenticate
to the remote host.
lmtp_sasl_path (default: empty)
Implementation-specific information that is passed through to
the SASL plug-in implementation that is selected with
lmtp_sasl_type. Typically this specifies the name of a
configuration file or rendezvous point.
This feature is available in Postfix 2.3 and later.
SASL security options; as of Postfix 2.3 the list of available
features depends on the SASL client implementation that is selected
with lmtp_sasl_type.
The following security features are defined for the cyrus
client SASL implementation:
noplaintext
Disallow authentication methods that use plaintext passwords.
noactive
Disallow authentication methods that are vulnerable to non-dictionary
active attacks.
nodictionary
Disallow authentication methods that are vulnerable to passive
dictionary attack.
The LMTP-specific version of the
smtp_sasl_tls_verified_security_options configuration parameter.
See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_sasl_type (default: cyrus)
The SASL plug-in type that the Postfix LMTP client should use
for authentication. The available types are listed with the
"postconf -A" command.
This feature is available in Postfix 2.3 and later.
lmtp_send_xforward_command (default: no)
Send an XFORWARD command to the LMTP server when the LMTP LHLO
server response announces XFORWARD support. This allows an lmtp(8)
delivery agent, used for content filter message injection, to
forward the name, address, protocol and HELO name of the original
client to the content filter and downstream queuing LMTP server.
Before you change the value to yes, it is best to make sure that
your content filter supports this command.
This feature is available in Postfix 2.1 and later.
The LMTP-specific version of the smtp_tls_mandatory_protocols
configuration parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_tls_note_starttls_offer (default: no)
The LMTP-specific version of the smtp_tls_note_starttls_offer
configuration parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_tls_per_site (default: empty)
The LMTP-specific version of the smtp_tls_per_site configuration
parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_tls_policy_maps (default: empty)
The LMTP-specific version of the smtp_tls_policy_maps
configuration parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_tls_scert_verifydepth (default: 5)
The LMTP-specific version of the smtp_tls_scert_verifydepth
configuration parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_tls_secure_cert_match (default: nexthop)
The LMTP-specific version of the smtp_tls_secure_cert_match
configuration parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_tls_session_cache_database (default: empty)
The LMTP-specific version of the smtp_tls_session_cache_database
configuration parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_tls_session_cache_timeout (default: 3600s)
The LMTP-specific version of the smtp_tls_session_cache_timeout
configuration parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_tls_verify_cert_match (default: hostname)
The LMTP-specific version of the smtp_tls_verify_cert_match
configuration parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_use_tls (default: no)
The LMTP-specific version of the smtp_use_tls configuration
parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_xforward_timeout (default: 300s)
The LMTP client time limit for sending the XFORWARD command, and
for receiving the server response.
In case of problems the client does NOT try the next address on
the mail exchanger list.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is s (seconds).
This feature is available in Postfix 2.1 and later.
local_command_shell (default: empty)
Optional shell program for local(8) delivery to non-Postfix command.
By default, non-Postfix commands are executed directly; commands
are given to given to /bin/sh only when they contain shell meta
characters or shell built-in commands.
"sendmail's restricted shell" (smrsh) is what most people will
use in order to restrict what programs can be run from e.g. .forward
files (smrsh is part of the Sendmail distribution).
Note: when a shell program is specified, it is invoked even
when the command contains no shell built-in commands or meta
characters.
Example:
local_command_shell = /some/where/smrsh -c
local_destination_concurrency_limit (default: 2)
The maximal number of parallel deliveries via the local mail
delivery transport to the same recipient (when
"local_destination_recipient_limit = 1") or the maximal number of
parallel deliveries to the same local domain (when
"local_destination_recipient_limit > 1"). This limit is enforced by
the queue manager. The message delivery transport name is the first
field in the entry in the master.cf file.
A low limit of 2 is recommended, just in case someone has an
expensive shell command in a .forward file or in an alias (e.g.,
a mailing list manager). You don't want to run lots of those at
the same time.
local_destination_recipient_limit (default: 1)
The maximal number of recipients per message delivery via the
local mail delivery transport. This limit is enforced by the queue
manager. The message delivery transport name is the first field in
the entry in the master.cf file.
Setting this parameter to a value > 1 changes the meaning of
local_destination_concurrency_limit from concurrency per recipient
into concurrency per domain.
Rewrite message header addresses in mail from these clients and
update incomplete addresses with the domain name in $myorigin or
$mydomain; either don't rewrite message headers from other clients
at all, or rewrite message headers and update incomplete addresses
with the domain specified in the remote_header_rewrite_domain
parameter.
See the append_at_myorigin and append_dot_mydomain parameters
for details of how domain names are appended to incomplete addresses.
Specify a list of zero or more of the following:
permit_inet_interfaces
Append the domain name in $myorigin or $mydomain when the
client IP address matches $inet_interfaces. This is enabled by
default.
permit_mynetworks
Append the domain name in $myorigin or $mydomain when the
client IP address matches any network or network address listed in
$mynetworks. This setting will not prevent remote mail header
address rewriting when mail from a remote client is forwarded by
a neighboring system.
permit_sasl_authenticated
Append the domain name in $myorigin or $mydomain when the
client is successfully authenticated via the RFC 2554 (AUTH)
protocol.
permit_tls_clientcerts
Append the domain name in $myorigin or $mydomain when the
client TLS certificate is successfully verified, and the client
certificate fingerprint is listed in $relay_clientcerts.
permit_tls_all_clientcerts
Append the domain name in $myorigin or $mydomain when the
client TLS certificate is successfully verified, regardless of
whether it is listed on the server, and regardless of the certifying
authority.
check_address_map type:table
type:table
Append the domain name in $myorigin or $mydomain when the
client IP address matches the specified lookup table.
The lookup result is ignored, and no subnet lookup is done. This
is suitable for, e.g., pop-before-smtp lookup tables.
Examples:
The Postfix < 2.2 backwards compatible setting: always rewrite
message headers, and always append my own domain to incomplete
header addresses.
local_header_rewrite_clients = static:all
The purist (and default) setting: rewrite headers only in mail
from Postfix sendmail and in SMTP mail from this machine.
The intermediate setting: rewrite header addresses and append
$myorigin or $mydomain information only with mail from Postfix
sendmail, from local clients, or from authorized SMTP clients.
Note: this setting will not prevent remote mail header address
rewriting when mail from a remote client is forwarded by a neighboring
system.
Lookup tables with all names or addresses of local recipients:
a recipient address is local when its domain matches $mydestination,
$inet_interfaces or $proxy_interfaces. Specify @domain as a
wild-card for domains that do not have a valid recipient list.
Technically, tables listed with $local_recipient_maps are used as
lists: Postfix needs to know only if a lookup string is found or
not, but it does not use the result from table lookup.
If this parameter is non-empty (the default), then the Postfix SMTP
server will reject mail for unknown local users.
To turn off local recipient checking in the Postfix SMTP server,
specify "local_recipient_maps =" (i.e. empty).
The default setting assumes that you use the default Postfix local
delivery agent for local delivery. You need to update the
local_recipient_maps setting if:
*
You redefine the local delivery agent in master.cf.
*
You redefine the "local_transport" setting in main.cf.
*
You use the "luser_relay", "mailbox_transport", or "fallback_transport"
feature of the Postfix local(8) delivery agent.
Details are described in the LOCAL_RECIPIENT_README file.
Beware: if the Postfix SMTP server runs chrooted, you need to access
the passwd file via the proxymap(8) service, in order to overcome
chroot access restrictions. The alternative, maintaining a copy of
the system password file in the chroot jail is not practical.
Examples:
local_recipient_maps =
local_transport (default: local:$myhostname)
The default mail delivery transport and next-hop destination
for final delivery to domains listed with mydestination, and for
[ipaddress] destinations that match $inet_interfaces or $proxy_interfaces.
This information can be overruled with the transport(5) table.
By default, local mail is delivered to the transport called "local",
which is just the name of a service that is defined the master.cf file.
Specify a string of the form transport:nexthop, where transport
is the name of a mail delivery transport defined in master.cf.
The :nexthop part is optional. For more details see the
transport(5) manual page.
Beware: if you override the default local delivery agent then you
need to review the LOCAL_RECIPIENT_README document, otherwise the
SMTP server may reject mail for local recipients.
luser_relay (default: empty)
Optional catch-all destination for unknown local(8) recipients.
By default, mail for unknown recipients in domains that match
$mydestination, $inet_interfaces or $proxy_interfaces is returned
as undeliverable.
The following $name expansions are done on luser_relay:
$domain
The recipient domain.
$extension
The recipient address extension.
$home
The recipient's home directory.
$local
The entire recipient address localpart.
$recipient
The full recipient address.
$recipient_delimiter
The system-wide recipient address extension delimiter.
$shell
The recipient's login shell.
$user
The recipient username.
${name?value}
Expands to value when $name has a non-empty value.
${name:value}
Expands to value when $name has an empty value.
Instead of $name you can also specify ${name} or $(name).
Note: luser_relay works only for the Postfix local(8) delivery agent.
Note: if you use this feature for accounts not in the UNIX password
file, then you must specify "local_recipient_maps =" (i.e. empty)
in the main.cf file, otherwise the Postfix SMTP server will reject mail
for non-UNIX accounts with "User unknown in local recipient table".
The mail system name that is displayed in Received: headers, in
the SMTP greeting banner, and in bounced mail.
mail_owner (default: postfix)
The UNIX system account that owns the Postfix queue and most Postfix
daemon processes. Specify the name of a user account that does
not share a group with other accounts and that owns no other files
or processes on the system. In particular, don't specify nobody
or daemon. PLEASE USE A DEDICATED USER ID AND GROUP ID.
When this parameter value is changed you need to re-run "postfix
set-permissions" (with Postfix version 2.0 and earlier:
"/etc/postfix/post-install set-permissions".
mail_release_date (default: see postconf -d output)
The Postfix release date, in "YYYYMMDD" format.
mail_spool_directory (default: see postconf -d output)
The directory where local(8) UNIX-style mailboxes are kept. The
default setting depends on the system type. Specify a name ending
in / for maildir-style delivery.
Note: maildir delivery is done with the privileges of the recipient.
If you use the mail_spool_directory setting for maildir style
delivery, then you must create the top-level maildir directory in
advance. Postfix will not create it.
The version of the mail system. Stable releases are named
major.minor.patchlevel. Experimental releases
also include the release date. The version string can be used in,
for example, the SMTP greeting banner.
mailbox_command (default: empty)
Optional external command that the local(8) delivery agent should
use for mailbox delivery. The command is run with the user ID and
the primary group ID privileges of the recipient. Exception:
command delivery for root executes with $default_privs privileges.
This is not a problem, because 1) mail for root should always be
aliased to a real user and 2) don't log in as root, use "su" instead.
The following environment variables are exported to the command:
CLIENT_ADDRESS
Remote client network address. Available in Postfix version 2.2 and
later.
CLIENT_HELO
Remote client EHLO command parameter. Available in Postfix version 2.2
and later.
CLIENT_HOSTNAME
Remote client hostname. Available in Postfix version 2.2 and later.
CLIENT_PROTOCOL
Remote client protocol. Available in Postfix version 2.2 and later.
DOMAIN
The domain part of the recipient address.
EXTENSION
The optional address extension.
HOME
The recipient home directory.
LOCAL
The recipient address localpart.
LOGNAME
The recipient's username.
RECIPIENT
The full recipient address.
SASL_METHOD
SASL authentication method specified in the remote client AUTH
command. Available in Postfix version 2.2 and later.
SASL_SENDER
SASL sender address specified in the remote client MAIL FROM
command. Available in Postfix version 2.2 and later.
SASL_USER
SASL username specified in the remote client AUTH command.
Available in Postfix version 2.2 and later.
SENDER
The full sender address.
SHELL
The recipient's login shell.
USER
The recipient username.
Unlike other Postfix configuration parameters, the mailbox_command
parameter is not subjected to $name substitutions. This is to make
it easier to specify shell syntax (see example below).
If you can, avoid shell meta characters because they will force
Postfix to run an expensive shell process. If you're delivering
via Procmail then running a shell won't make a noticeable difference
in the total cost.
Note: if you use the mailbox_command feature to deliver mail
system-wide, you must set up an alias that forwards mail for root
to a real user.
The precedence of local(8) delivery features from high to low
is: aliases, .forward files, mailbox_transport_maps, mailbox_transport,
mailbox_command_maps, mailbox_command, home_mailbox, mail_spool_directory,
fallback_transport_maps, fallback_transport and luser_relay.
Optional lookup tables with per-recipient external commands to use
for local(8) mailbox delivery. Behavior is as with mailbox_command.
The precedence of local(8) delivery features from high to low
is: aliases, .forward files, mailbox_transport_maps, mailbox_transport,
mailbox_command_maps, mailbox_command, home_mailbox, mail_spool_directory,
fallback_transport_maps, fallback_transport and luser_relay.
mailbox_delivery_lock (default: see postconf -d output)
How to lock a UNIX-style local(8) mailbox before attempting delivery.
For a list of available file locking methods, use the "postconf
-l" command.
This setting is ignored with maildir style delivery,
because such deliveries are safe without explicit locks.
Note: The dotlock method requires that the recipient UID or
GID has write access to the parent directory of the mailbox file.
Note: the default setting of this parameter is system dependent.
mailbox_size_limit (default: 51200000)
The maximal size of any local(8) individual mailbox or maildir
file, or zero (no limit). In fact, this limits the size of any
file that is written to upon local delivery, including files written
by external commands that are executed by the local(8) delivery
agent.
This limit must not be smaller than the message size limit.
mailbox_transport (default: empty)
Optional message delivery transport that the local(8) delivery
agent should use for mailbox delivery to all local recipients,
whether or not they are found in the UNIX passwd database.
The precedence of local(8) delivery features from high to low
is: aliases, .forward files, mailbox_transport_maps, mailbox_transport,
mailbox_command_maps, mailbox_command, home_mailbox, mail_spool_directory,
fallback_transport_maps, fallback_transport and luser_relay.
mailbox_transport_maps (default: empty)
Optional lookup tables with per-recipient message delivery
transports to use for local(8) mailbox delivery, whether or not the
recipients are found in the UNIX passwd database.
The precedence of local(8) delivery features from high to low
is: aliases, .forward files, mailbox_transport_maps, mailbox_transport,
mailbox_command_maps, mailbox_command, home_mailbox, mail_spool_directory,
fallback_transport_maps, fallback_transport and luser_relay.
For safety reasons, this feature does not allow $number
substitutions in regular expression maps.
This feature is available in Postfix 2.3 and later.
mailq_path (default: see postconf -d output)
Sendmail compatibility feature that specifies where the Postfix
mailq(1) command is installed. This command can be used to
list the Postfix mail queue.
manpage_directory (default: see postconf -d output)
Where the Postfix manual pages are installed.
maps_rbl_domains (default: empty)
Obsolete feature: use the reject_rbl_client feature instead.
maps_rbl_reject_code (default: 554)
The numerical Postfix SMTP server response code when a remote SMTP
client request is blocked by the reject_rbl_client, reject_rhsbl_client,
reject_rhsbl_sender or reject_rhsbl_recipient restriction.
Do not change this unless you have a complete understanding of RFC 821.
What addresses are subject to address masquerading.
By default, address masquerading is limited to envelope sender
addresses, and to header sender and header recipient addresses.
This allows you to use address masquerading on a mail gateway while
still being able to forward mail to users on individual machines.
Specify zero or more of: envelope_sender, envelope_recipient,
header_sender, header_recipient
masquerade_domains (default: empty)
Optional list of domains whose subdomain structure will be stripped
off in email addresses.
The list is processed left to right, and processing stops at the
first match. Thus,
Note: with Postfix version 2.2, message header address masquerading
happens only when message header address rewriting is enabled:
*
The message is received with the Postfix sendmail(1) command,
*
The message is received from a network client that matches
$local_header_rewrite_clients,
*
The message is received from the network, and the
remote_header_rewrite_domain parameter specifies a non-empty value.
To get the behavior before Postfix version 2.2, specify
"local_header_rewrite_clients = static:all".
Example:
masquerade_domains = $mydomain
masquerade_exceptions (default: empty)
Optional list of user names that are not subjected to address
masquerading, even when their address matches $masquerade_domains.
By default, address masquerading makes no exceptions.
Specify a list of user names, "/file/name" or "type:table" patterns,
separated by commas and/or whitespace. The list is matched left to
right, and the search stops on the first match. Specify "!name" to
exclude a name from the list. A "/file/name" pattern is replaced
by its contents; a "type:table" lookup table is matched when a name
matches a lookup key (the lookup result is ignored). Continue long
lines by starting the next line with whitespace.
The maximum amount of time that an idle Postfix daemon process
waits for the next service request before exiting. This parameter
is ignored by the Postfix queue manager.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is s (seconds).
max_use (default: 100)
The maximal number of connection requests before a Postfix daemon
process terminates. This parameter is ignored by the Postfix queue
manager and by other long-lived Postfix daemon processes.
maximal_backoff_time (default: 4000s)
The maximal time between attempts to deliver a deferred message.
This parameter should be set to a value greater than or equal
to $minimal_backoff_time. See also $queue_run_delay.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is s (seconds).
maximal_queue_lifetime (default: 5d)
The maximal time a message is queued before it is sent back as
undeliverable.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is d (days).
Specify 0 when mail delivery should be tried only once.
message_reject_characters (default: empty)
The set of characters that Postfix will reject in message
content. The usual C-like escape sequences are recognized: \a
\b \f \n \r \t \v \ddd (up to three octal digits) and
\\.
Example:
message_reject_characters = \0
This feature is available in Postfix 2.3 and later.
message_size_limit (default: 10240000)
The maximal size in bytes of a message, including envelope information.
message_strip_characters (default: empty)
The set of characters that Postfix will remove from message
content. The usual C-like escape sequences are recognized: \a
\b \f \n \r \t \v \ddd (up to three octal digits) and
\\.
Example:
message_strip_characters = \0
This feature is available in Postfix 2.3 and later.
milter_command_timeout (default: 30s)
The time limit for sending an SMTP command to a Milter (mail
filter) application, and for receiving the response.
Specify a non-zero time value (an integral value plus an optional
one-letter suffix that specifies the time unit).
Time units: s (seconds), m (minutes), h (hours), d (days), w
(weeks). The default time unit is s (seconds).
This feature is available in Postfix 2.3 and later.
milter_connect_macros (default: see postconf -n output)
The macros that are sent to Milter (mail filter) applications
after completion of an SMTP connection. See MILTER_README
for a list of available macro names and their meanings.
This feature is available in Postfix 2.3 and later.
milter_connect_timeout (default: 30s)
The time limit for connecting to a Milter (mail filter)
application, and for negotiating protocol options.
Specify a non-zero time value (an integral value plus an optional
one-letter suffix that specifies the time unit).
Time units: s (seconds), m (minutes), h (hours), d (days), w
(weeks). The default time unit is s (seconds).
This feature is available in Postfix 2.3 and later.
milter_content_timeout (default: 300s)
The time limit for sending message content to a Milter (mail
filter) application, and for receiving the response.
Specify a non-zero time value (an integral value plus an optional
one-letter suffix that specifies the time unit).
Time units: s (seconds), m (minutes), h (hours), d (days), w
(weeks). The default time unit is s (seconds).
This feature is available in Postfix 2.3 and later.
milter_data_macros (default: see postconf -n output)
The macros that are sent to version 4 or higher Milter (mail
filter) applications after the SMTP DATA command. See MILTER_README
for a list of available macro names and their meanings.
This feature is available in Postfix 2.3 and later.
milter_default_action (default: tempfail)
The default action when a Milter (mail filter) application is
unavailable or mis-configured. Specify one of the following:
accept
Proceed as if the mail filter was not present.
reject
Reject all further commands in this session
with a permanent status code.
tempfail
Reject all further commands in this session
with a temporary status code.
This feature is available in Postfix 2.3 and later.
milter_end_of_data_macros (default: see postconf -n output)
The macros that are sent to Milter (mail filter) applications
after the message end-of-data. See MILTER_README for a list of
available macro names and their meanings.
This feature is available in Postfix 2.3 and later.
milter_helo_macros (default: see postconf -n output)
The macros that are sent to Milter (mail filter) applications
after the SMTP HELO or EHLO command. See
MILTER_README for a list of available macro names and their meanings.
This feature is available in Postfix 2.3 and later.
milter_macro_daemon_name (default: $myhostname)
The {daemon_name} macro value for Milter (mail filter) applications.
See MILTER_README for a list of available macro names and their
meanings.
This feature is available in Postfix 2.3 and later.
The {v} macro value for Milter (mail filter) applications.
See MILTER_README for a list of available macro names and their
meanings.
This feature is available in Postfix 2.3 and later.
milter_mail_macros (default: see postconf -n output)
The macros that are sent to Milter (mail filter) applications
after the SMTP MAIL FROM command. See MILTER_README
for a list of available macro names and their meanings.
This feature is available in Postfix 2.3 and later.
milter_protocol (default: 2)
The mail filter protocol version and optional protocol extensions
for communication with a Milter (mail filter) application. This
information should match the protocol that is expected by the actual
mail filter application.
Protocol versions:
2
Use Sendmail 8 mail filter protocol version 2.
3
Use Sendmail 8 mail filter protocol version 3.
4
Use Sendmail 8 mail filter protocol version 4.
Protocol extensions:
no_header_reply
Specify this when the Milter application
will not reply for each individual message header.
This feature is available in Postfix 2.3 and later.
milter_rcpt_macros (default: see postconf -n output)
The macros that are sent to Milter (mail filter) applications
after the SMTP RCPT TO command. See MILTER_README
for a list of available macro names and their meanings.
This feature is available in Postfix 2.3 and later.
milter_unknown_command_macros (default: see postconf -n output)
The macros that are sent to version 3 or higher Milter (mail
filter) applications after an unknown SMTP command. See MILTER_README
for a list of available macro names and their meanings.
This feature is available in Postfix 2.3 and later.
mime_boundary_length_limit (default: 2048)
The maximal length of MIME multipart boundary strings. The MIME
processor is unable to distinguish between boundary strings that
do not differ in the first $mime_boundary_length_limit characters.
This feature is available in Postfix 2.0 and later.
mime_header_checks (default: $header_checks)
Optional lookup tables for content inspection of MIME related
message headers, as described in the header_checks(5) manual page.
This feature is available in Postfix 2.0 and later.
mime_nesting_limit (default: 100)
The maximal recursion level that the MIME processor will handle.
Postfix refuses mail that is nested deeper than the specified limit.
This feature is available in Postfix 2.0 and later.
minimal_backoff_time (default: 1000s)
The minimal time between attempts to deliver a deferred message.
This parameter also limits the time an unreachable destination is
kept in the short-term, in-memory, destination status cache.
This parameter should be set greater than or equal to
$queue_run_delay. See also $maximal_backoff_time.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is s (seconds).
multi_recipient_bounce_reject_code (default: 550)
The numerical Postfix SMTP server response code when a remote SMTP
client request is blocked by the reject_multi_recipient_bounce
restriction.
Do not change this unless you have a complete understanding of RFC 821.
This feature is available in Postfix 2.1 and later.
The list of domains that are delivered via the $local_transport
mail delivery transport. By default this is the Postfix local(8)
delivery agent which looks up all recipients in /etc/passwd and
/etc/aliases. The SMTP server validates recipient addresses with
$local_recipient_maps and rejects non-existent recipients. See also
the local domain class in the ADDRESS_CLASS_README file.
The default mydestination value specifies names for the local
machine only. On a mail domain gateway, you should also include
$mydomain.
The $local_transport delivery method is also selected for mail
addressed to user@[the.net.work.address] of the mail system (the
IP addresses specified with the inet_interfaces and proxy_interfaces
parameters).
Warnings:
*
Do not specify the names of virtual domains - those domains
are specified elsewhere. See VIRTUAL_README for more information.
*
Do not specify the names of domains that this machine is
backup MX host for. See STANDARD_CONFIGURATION_README for how to
set up backup MX hosts.
*
By default, the Postfix SMTP server rejects mail for recipients
not listed with the local_recipient_maps parameter. See the
postconf(5) manual for a description of the local_recipient_maps
and unknown_local_recipient_reject_code parameters.
Specify a list of host or domain names, "/file/name" or "type:table"
patterns, separated by commas and/or whitespace. A "/file/name"
pattern is replaced by its contents; a "type:table" lookup table
is matched when a name matches a lookup key (the lookup result is
ignored). Continue long lines by starting the next line with
whitespace.
The internet domain name of this mail system. The default is to
use $myhostname minus the first component. $mydomain is used as
a default value for many other configuration parameters.
Example:
mydomain = domain.tld
myhostname (default: see postconf -d output)
The internet hostname of this mail system. The default is to use
the fully-qualified domain name from gethostname(). $myhostname is
used as a default value for many other configuration parameters.
Example:
myhostname = host.domain.tld
mynetworks (default: see postconf -d output)
The list of "trusted" SMTP clients that have more privileges than
"strangers".
In particular, "trusted" SMTP clients are allowed to relay mail
through Postfix. See the smtpd_recipient_restrictions parameter
description in the postconf(5) manual.
You can specify the list of "trusted" network addresses by hand
or you can let Postfix do it for you (which is the default).
See the description of the mynetworks_style parameter for more
information.
If you specify the mynetworks list by hand,
Postfix ignores the mynetworks_style setting.
Specify a list of network addresses or network/netmask patterns,
separated by commas and/or whitespace. Continue long lines by
starting the next line with whitespace.
The netmask specifies the number of bits in the network part
of a host address. You can also specify "/file/name" or "type:table"
patterns. A "/file/name" pattern is replaced by its contents; a
"type:table" lookup table is matched when a table entry matches a
lookup string (the lookup result is ignored).
The list is matched left to right, and the search stops on the
first match. Specify "!pattern" to exclude an address or network
block from the list.
Note: IP version 6 address information must be specified inside
[] in the mynetworks value, and in files specified with
"/file/name". IP version 6 addresses contain the ":" character,
and would otherwise be confused with a "type:table" pattern.
The method to generate the default value for the mynetworks parameter.
This is the list of trusted networks for relay access control etc.
*
Specify "mynetworks_style = host" when Postfix should
"trust" only the local machine.
*
Specify "mynetworks_style = subnet" when Postfix
should "trust" SMTP clients in the same IP subnetworks as the local
machine. On Linux, this works correctly only with interfaces
specified with the "ifconfig" command.
*
Specify "mynetworks_style = class" when Postfix should
"trust" SMTP clients in the same IP class A/B/C networks as the
local machine. Don't do this with a dialup site - it would cause
Postfix to "trust" your entire provider's network. Instead, specify
an explicit mynetworks list by hand, as described with the mynetworks
configuration parameter.
myorigin (default: $myhostname)
The domain name that locally-posted mail appears to come
from, and that locally posted mail is delivered to. The default,
$myhostname, is adequate for small sites. If you run a domain with
multiple machines, you should (1) change this to $mydomain and (2)
set up a domain-wide alias database that aliases each user to
user@that.users.mailhost.
Example:
myorigin = $mydomain
nested_header_checks (default: $header_checks)
Optional lookup tables for content inspection of non-MIME message
headers in attached messages, as described in the header_checks(5)
manual page.
This feature is available in Postfix 2.0 and later.
newaliases_path (default: see postconf -d output)
Sendmail compatibility feature that specifies the location of the
newaliases(1) command. This command can be used to rebuild the
local(8) aliases(5) database.
non_fqdn_reject_code (default: 504)
The numerical Postfix SMTP server reply code when a client request
is rejected by the reject_non_fqdn_helo_hostname, reject_non_fqdn_sender
or reject_non_fqdn_recipient restriction.
non_smtpd_milters (default: empty)
A list of Milter (mail filter) applications for new mail that
does not arrive via the Postfix smtpd(8) server. This includes local
submission via the sendmail(1) command line, new mail that arrives
via the Postfix qmqpd(8) server, and old mail that is re-injected
into the queue with "postsuper -r". See the MILTER_README document
for details.
This feature is available in Postfix 2.3 and later.
notify_classes (default: resource, software)
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 (UCE and mail relaying) and protocol
error (broken mail software) reports.
NOTE: postmaster notifications may contain confidential information
such as SASL passwords or message content. It is the system
administrator's responsibility to treat such information with care.
The error classes are:
bounce (also implies 2bounce)
Send the postmaster copies of the headers of bounced mail, and
send transcripts of SMTP sessions when Postfix rejects mail. The
notification is sent to the address specified with the
bounce_notice_recipient configuration parameter (default: postmaster).
2bounce
Send undeliverable bounced mail to the postmaster. The notification
is sent to the address specified with the 2bounce_notice_recipient
configuration parameter (default: postmaster).
delay
Send the postmaster copies of the headers of delayed mail. The
notification is sent to the address specified with the
delay_notice_recipient configuration parameter (default: postmaster).
policy
Send the postmaster a transcript of the SMTP session when a
client request was rejected because of (UCE) policy. The notification
is sent to the address specified with the error_notice_recipient
configuration parameter (default: postmaster).
protocol
Send the postmaster a transcript of the SMTP session in case
of client or server protocol errors. The notification is sent to
the address specified with the error_notice_recipient configuration
parameter (default: postmaster).
resource
Inform the postmaster of mail not delivered due to resource
problems. The notification is sent to the address specified with
the error_notice_recipient configuration parameter (default:
postmaster).
software
Inform the postmaster of mail not delivered due to software
problems. The notification is sent to the address specified with
the error_notice_recipient configuration parameter (default:
postmaster).
Give special treatment to owner-listname and listname-request
address localparts: don't split such addresses when the
recipient_delimiter is set to "-". This feature is useful for
mailing lists.
parent_domain_matches_subdomains (default: see postconf -d output)
What Postfix features match subdomains of "domain.tld" automatically,
instead of requiring an explicit ".domain.tld" pattern. This is
planned backwards compatibility: eventually, all Postfix features
are expected to require explicit ".domain.tld" style patterns when
you really want to match subdomains.
permit_mx_backup_networks (default: empty)
Restrict the use of the permit_mx_backup SMTP access feature to
only domains whose primary MX hosts match the listed networks.
pickup_service_name (default: pickup)
The name of the pickup(8) service. This service picks up local mail
submissions from the Postfix maildrop queue.
This feature is available in Postfix 2.0 and later.
plaintext_reject_code (default: 450)
The numerical Postfix SMTP server response code when a request
is rejected by the reject_plaintext_session restriction.
This feature is available in Postfix 2.3 and later.
The message delivery contexts where the Postfix local(8) delivery
agent prepends a Delivered-To: message header with the address
that the mail was delivered to. This information is used for mail
delivery loop detection.
By default, the Postfix local delivery agent prepends a Delivered-To:
header when forwarding mail and when delivering to file (mailbox)
and command. Turning off the Delivered-To: header when forwarding
mail is not recommended.
Specify zero or more of forward, file, or command.
Example:
prepend_delivered_header = forward
process_id (read-only)
The process ID of a Postfix command or daemon process.
process_id_directory (default: pid)
The location of Postfix PID files relative to $queue_directory.
This is a read-only parameter.
process_name (read-only)
The process name of a Postfix command or daemon process.
What address lookup tables copy an address extension from the lookup
key to the lookup result.
For example, with a virtual(5) mapping of "joe@domain ->
joe.user", the address "joe+foo@domain" would rewrite
to "joe.user+foo".Segmentation fault (core dumped)
