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POSTCONF(5) POSTCONF(5)
NAME
postconf - Postfix configuration parameters
SYNOPSIS
postconf parameter ...
postconf -e "parameter=value" ...
DESCRIPTION
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 log-
ical 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 configu-
ration 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 configura-
tion 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.
address_verify_default_transport (default: $default_transport)
Overrides the default_transport parameter setting for address verifica-
tion probes.
This feature is available in Postfix 2.1 and later.
address_verify_local_transport (default: $local_transport)
Overrides the local_transport parameter setting for address verifica-
tion probes.
This feature is available in Postfix 2.1 and later.
address_verify_map (default: empty)
Optional lookup table for persistent address verification status stor-
age. 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".
Examples:
address_verify_map = hash:/etc/postfix/verify
address_verify_map = btree:/etc/postfix/verify
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 verifica-
tion cache.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
This feature is available in Postfix 2.1 and later.
address_verify_negative_refresh_time (default: 3h)
The time after which a failed address verification probe needs to be
refreshed.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
This feature is available in Postfix 2.1 and later.
address_verify_poll_count (default: 3)
How many times to query the verify(8) service for the completion of an
address verification request in progress.
The default poll count is 3.
Specify 1 to implement a crude form of greylisting, that is, always
defer the first delivery request for a never seen before address.
Example:
address_verify_poll_count = 1
This feature is available in Postfix 2.1 and later.
address_verify_poll_delay (default: 3s)
The delay between queries for the completion of an address verification
request in progress.
The default polling delay is 3 seconds.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
This feature is available in Postfix 2.1 and later.
address_verify_positive_expire_time (default: 31d)
The time after which a successful probe expires from the address veri-
fication cache.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
This feature is available in Postfix 2.1 and later.
address_verify_positive_refresh_time (default: 7d)
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.
address_verify_relay_transport (default: $relay_transport)
Overrides the relay_transport parameter setting for address verifica-
tion 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.
Examples:
address_verify_sender = <>
address_verify_sender = postmaster@my.domain
This feature is available in Postfix 2.1 and later.
address_verify_sender_dependent_relayhost_maps (default: empty)
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.
address_verify_transport_maps (default: $transport_maps)
Overrides the transport_maps parameter setting for address verification
probes.
This feature is available in Postfix 2.1 and later.
address_verify_virtual_transport (default: $virtual_transport)
Overrides the virtual_transport parameter setting for address verifica-
tion probes.
This feature is available in Postfix 2.1 and later.
alias_database (default: see postconf -d output)
The alias databases for local(8) delivery that are updated with
"newaliases" or with "sendmail -bi".
This is a separate configuration parameter because not all the tables
specified with $alias_maps have to be local files.
Examples:
alias_database = hash:/etc/aliases
alias_database = hash:/etc/mail/aliases
alias_maps (default: see postconf -d output)
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.
Examples:
alias_maps = hash:/etc/aliases, nis:mail.aliases
alias_maps = hash:/etc/aliases
allow_mail_to_commands (default: alias, forward)
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, respec-
tively.
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 ter-
minator into the command line, this is difficult to enforce consis-
tently 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 hap-
pens 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-speci-
fied 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 direc-
tory, 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, infor-
mation 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 hap-
pens 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 hap-
pens 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 pass-
word 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 pass-
word 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 com-
mand 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 ver-
sion 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.
backwards_bounce_logfile_compatibility (default: yes)
Produce additional bounce(8) logfile records that can be read by Post-
fix versions before 2.0. The current and more extensible "name = value"
format is needed in order to implement more sophisticated functional-
ity.
This feature is available in Postfix 2.1 and later.
berkeley_db_create_buffer_size (default: 16777216)
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, $vir-
tual_alias_domains, or $virtual_mailbox_domains. By default, the Post-
fix 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 propor-
tionally.
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 con-
figuration 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.
canonical_classes (default: envelope_sender, envelope_recipient,
header_sender, header_recipient)
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 First-
name.Lastname. The table format and lookups are documented in canoni-
cal(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".
Examples:
canonical_maps = dbm:/etc/postfix/canonical
canonical_maps = hash:/etc/postfix/canonical
cleanup_service_name (default: cleanup)
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_expan-
sion_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 com-
mands).
· The "-c" command-line option (commands only).
With Postfix command that run with set-gid privileges, a config_direc-
tory 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 main-
tains a limited pool of cached sessions.
connection_cache_status_update_time (default: 600s)
How frequently the scache(8) server logs usage statistics with connec-
tion 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 par-
ent_domain_matches_subdomains parameter.
Examples:
debug_peer_list = 127.0.0.1
debug_peer_list = some.domain
debugger_command (default: empty)
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.
Example:
debugger_command =
PATH=/usr/bin:/usr/X11R6/bin
xxgdb $daemon_directory/$process_name $process_id & sleep 5
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.
Examples:
default_database_type = hash
default_database_type = dbm
default_delivery_slot_cost (default: 5)
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 max-
imum, 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.
Examples:
default_delivery_slot_cost = 0
default_delivery_slot_cost = 2
default_delivery_slot_discount (default: 50)
The default value for transport-specific _delivery_slot_discount set-
tings.
This parameter speeds up the moment when a message preemption can hap-
pen. Instead of waiting until the full amount of delivery slots
required is available, the preemption can happen when transport_deliv-
ery_slot_discount percent of the required amount plus transport_deliv-
ery_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 hap-
pen. Instead of waiting until the full amount of delivery slots
required is available, the preemption can happen when transport_deliv-
ery_slot_discount percent of the required amount plus transport_deliv-
ery_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_destination_concurrency_limit (default: 20)
The default maximal number of parallel deliveries to the same destina-
tion. 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 cor-
responding 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 num-
ber 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 deliv-
ery 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 numeri-
cal SMTP response code is required, and must appear at the start
of the reply. With Postfix version 2.3 and later this informa-
tion 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 tem-
plate, 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 recip-
ients. These limits take priority over the global qmgr_message_recipi-
ent_limit after the message has been assigned to the respective trans-
ports. See also default_extra_recipient_limit and qmgr_message_recipi-
ent_minimum.
default_transport (default: smtp)
The default mail delivery transport and next-hop destination for desti-
nations 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 desti-
nation is taken from $default_transport, $sender_dependent_relay-
host_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 transmis-
sion
· 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 mail-
box 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 dis-
abled, hosts are looked up with the gethostbyname() system library rou-
tine 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 spe-
cial 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 har-
vest 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-stan-
dard 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, rewrit-
ten recipient), and generates non-empty original recipient queue file
records.
When this parameter is set to no, the cleanup(8) daemon performs dupli-
cate 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 ver-
sion 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 whites-
pace 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, Post-
fix 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 pass-
word 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_direc-
tory, 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 destina-
tions 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:ta-
ble" 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 let-
ter 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 let-
ter 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-destina-
tion 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 $(name).
Examples:
forward_path = /var/forward/$user
forward_path =
/var/forward/$user/.forward$recipient_delimiter$extension,
/var/forward/$user/.forward
frozen_delivered_to (default: yes)
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, exe-
cute the command "postfix reload".
hash_queue_names (default: deferred, defer)
The names of queue directories that are split across multiple subdirec-
tory levels.
Before Postfix version 2.2, the default list of hashed queues was sig-
nificantly 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, exe-
cute 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 mes-
sage 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_direc-
tory, 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, config-
ure 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 Post-
fix 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 whites-
pace 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 mas-
ter.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 use-
ful with virtual hosting of domains on secondary IP addresses, when
each IP address serves a different domain (and has a different $myhost-
name 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", sepa-
rated 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.
Examples:
inet_protocols = ipv4 (DEFAULT)
inet_protocols = all
inet_protocols = ipv6
inet_protocols = ipv4, ipv6
initial_destination_concurrency (default: 5)
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 situa-
tions. 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 param-
eter. 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 num-
ber 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 spec-
ified 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 con-
figuration 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 con-
figuration 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).
Example:
lmtp_connect_timeout = 30s
lmtp_connection_cache_destinations (default: empty)
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 con-
figuration 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 con-
figuration 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 con-
figuration 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 con-
figuration parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_destination_concurrency_limit (default: $default_destination_concur-
rency_limit)
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.
lmtp_destination_recipient_limit (default: $default_destination_recipi-
ent_limit)
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_des-
tination_concurrency_limit from concurrency per domain into concurrency
per recipient.
lmtp_discard_lhlo_keyword_address_maps (default: empty)
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_key-
word_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 dis-
card LHLO keywords selectively.
lmtp_enforce_tls (default: no)
The LMTP-specific version of the smtp_enforce_tls configuration parame-
ter. 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 param-
eter. 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 parame-
ter. 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:
/etc/postfix/master.cf:
mylmtp ... lmtp -o lmtp_lhlo_name=foo.bar.com
This feature is available in Postfix 2.3 and later.
lmtp_lhlo_timeout (default: 300s)
The LMTP client time limit for sending the LHLO command, and for
receiving the initial server response.
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is s (seconds).
lmtp_line_length_limit (default: 990)
The LMTP-specific version of the smtp_line_length_limit configuration
parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_mail_timeout (default: 300s)
The LMTP client time limit for sending the MAIL FROM 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_mx_address_limit (default: 5)
The LMTP-specific version of the smtp_mx_address_limit configuration
parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_mx_session_limit (default: 2)
The LMTP-specific version of the smtp_mx_session_limit configuration
parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_pix_workaround_delay_time (default: 10s)
The LMTP-specific version of the smtp_pix_workaround_delay_time config-
uration parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_pix_workaround_threshold_time (default: 500s)
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 configura-
tion 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 configura-
tion 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.
lmtp_sasl_security_options (default: noplaintext, noanonymous)
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-dic-
tionary active attacks.
nodictionary
Disallow authentication methods that are vulnerable to passive
dictionary attack.
noanonymous
Disallow anonymous logins.
Example:
lmtp_sasl_security_options = noplaintext
lmtp_sasl_tls_security_options (default: $lmtp_sasl_security_options)
The LMTP-specific version of the smtp_sasl_tls_security_options config-
uration parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_sasl_tls_verified_security_options (default: $lmtp_sasl_tls_secu-
rity_options)
The LMTP-specific version of the smtp_sasl_tls_verified_secu-
rity_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.
lmtp_sender_dependent_authentication (default: no)
The LMTP-specific version of the smtp_sender_dependent_authentication
configuration parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_skip_5xx_greeting (default: yes)
The LMTP-specific version of the smtp_skip_5xx_greeting configuration
parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_skip_quit_response (default: no)
Wait for the response to the LMTP QUIT command.
lmtp_starttls_timeout (default: 300s)
The LMTP-specific version of the smtp_starttls_timeout configuration
parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_tcp_port (default: 24)
The default TCP port that the Postfix LMTP client connects to.
lmtp_tls_CAfile (default: empty)
The LMTP-specific version of the smtp_tls_CAfile configuration parame-
ter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_tls_CApath (default: empty)
The LMTP-specific version of the smtp_tls_CApath configuration parame-
ter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_tls_cert_file (default: empty)
The LMTP-specific version of the smtp_tls_cert_file configuration
parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_tls_dcert_file (default: empty)
The LMTP-specific version of the smtp_tls_dcert_file configuration
parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_tls_dkey_file (default: $lmtp_tls_dcert_file)
The LMTP-specific version of the smtp_tls_dkey_file configuration
parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_tls_enforce_peername (default: yes)
The LMTP-specific version of the smtp_tls_enforce_peername configura-
tion parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_tls_exclude_ciphers (default: empty)
The LMTP-specific version of the smtp_tls_exclude_ciphers configuration
parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_tls_key_file (default: $lmtp_tls_cert_file)
The LMTP-specific version of the smtp_tls_key_file configuration param-
eter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_tls_loglevel (default: 0)
The LMTP-specific version of the smtp_tls_loglevel configuration param-
eter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_tls_mandatory_ciphers (default: empty)
The LMTP-specific version of the smtp_tls_mandatory_ciphers configura-
tion parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_tls_mandatory_exclude_ciphers (default: empty)
The LMTP-specific version of the smtp_tls_mandatory_exclude_ciphers
configuration parameter. See there for details.
This feature is available in Postfix 2.3 and later.
lmtp_tls_mandatory_protocols (default: SSLv3, TLSv1)
The LMTP-specific version of the smtp_tls_mandatory_protocols configu-
ration 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 configu-
ration 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 param-
eter. 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 configura-
tion 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 configura-
tion 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 con-
figuration 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 config-
uration 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 configura-
tion 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_recipi-
ent_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_des-
tination_concurrency_limit from concurrency per recipient into concur-
rency per domain.
local_header_rewrite_clients (default: permit_inet_interfaces)
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 cer-
tificate 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 suit-
able 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.
local_header_rewrite_clients = permit_inet_interfaces
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 rewrit-
ing when mail from a remote client is forwarded by a neighboring sys-
tem.
local_header_rewrite_clients = permit_mynetworks,
permit_sasl_authenticated permit_tls_clientcerts
check_address_map hash:/etc/postfix/pop-before-smtp
local_recipient_maps (default: proxy:unix:passwd.byname $alias_maps)
Lookup tables with all names or addresses of local recipients: a recip-
ient 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 $local_recipient_maps are used as lists: Postfix
needs to know only if a lookup string is found or not, but it does not
use the result from table lookup.
If this parameter is non-empty (the default), then the Postfix SMTP
server will reject mail for unknown local users.
To turn off local recipient checking in the Postfix SMTP server, spec-
ify "local_recipient_maps =" (i.e. empty).
The default setting assumes that you use the default Postfix local
delivery agent for local delivery. You need to update the local_recipi-
ent_maps setting if:
· You redefine the local delivery agent in master.cf.
· You redefine the "local_transport" setting in main.cf.
· You use the "luser_relay", "mailbox_transport", or "fall-
back_transport" feature of the Postfix local(8) delivery agent.
Details are described in the LOCAL_RECIPIENT_README file.
Beware: if the Postfix SMTP server runs chrooted, you need to access
the passwd file via the proxymap(8) service, in order to overcome
chroot access restrictions. The alternative, maintaining a copy of the
system password file in the chroot jail is not practical.
Examples:
local_recipient_maps =
local_transport (default: local:$myhostname)
The default mail delivery transport and next-hop destination for final
delivery to domains listed with mydestination, and for [ipaddress] des-
tinations 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 $mydestina-
tion, $inet_interfaces or $proxy_interfaces is returned as undeliver-
able.
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".
Examples:
luser_relay = $user@other.host
luser_relay = $local@other.host
luser_relay = admin+$local
mail_name (default: Postfix)
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 pro-
cesses 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. Post-
fix will not create it.
Examples:
mail_spool_directory = /var/mail
mail_spool_directory = /var/spool/mail
mail_version (default: see postconf -d output)
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 pri-
mary group ID privileges of the recipient. Exception: command delivery
for root executes with $default_privs privileges. This is not a prob-
lem, 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 ver-
sion 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 se |
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