CLEANUP(8) System Manager's Manual CLEANUP(8)
NAME
cleanup - canonicalize and enqueue Postfix message
SYNOPSIS
cleanup [generic Postfix daemon options]
DESCRIPTION
The cleanup(8) daemon processes inbound mail, inserts it into the in‐
coming mail queue, and informs the queue manager of its arrival.
The cleanup(8) daemon performs the following transformations:
• Insert missing message headers: (Resent-) From:, To:, Mes‐
sage-Id:, and Date:.
This is enabled with the local_header_rewrite_clients and al‐
ways_add_missing_headers parameter settings.
• Transform envelope and header addresses to the standard
user@fully-qualified-domain form that is expected by other Post‐
fix programs. This task depends on the trivial-rewrite(8) dae‐
mon.
The header transformation is enabled with the local_header_re‐
write_clients parameter setting.
• Eliminate duplicate envelope recipient addresses.
This is enabled with the duplicate_filter_limit parameter set‐
ting.
• Remove message headers: Bcc, Content-Length, Resent-Bcc, Re‐
turn-Path.
This is enabled with the message_drop_headers parameter setting.
• Optionally, rewrite all envelope and header addresses according
to the mappings specified in the canonical(5) lookup tables.
The header transformation is enabled with the local_header_re‐
write_clients parameter setting.
• Optionally, masquerade envelope sender addresses and message
header addresses (i.e. strip host or domain information below
all domains listed in the masquerade_domains parameter, except
for user names listed in masquerade_exceptions). By default,
address masquerading does not affect envelope recipients.
The header transformation is enabled with the local_header_re‐
write_clients parameter setting.
• Optionally, expand envelope recipients according to information
found in the virtual_alias_maps lookup tables.
The cleanup(8) daemon performs sanity checks on the content of each
message. When it finds a problem, by default it returns a diagnostic
status to the cleanup service client, and leaves it up to the client to
deal with the problem. Alternatively, the client can request the
cleanup(8) daemon to bounce the message back to the sender in case of
trouble.
STANDARDS
RFC 822 (ARPA Internet Text Messages)
RFC 2045 (MIME: Format of Internet Message Bodies)
RFC 2046 (MIME: Media Types)
RFC 2822 (Internet Message Format)
RFC 3463 (Enhanced Status Codes)
RFC 3464 (Delivery status notifications)
RFC 5322 (Internet Message Format)
DIAGNOSTICS
Problems and transactions are logged to syslogd(8) or postlogd(8).
BUGS
Table-driven rewriting rules make it hard to express if then else and
other logical relationships.
CONFIGURATION PARAMETERS
Changes to main.cf are picked up automatically, as cleanup(8) processes
run for only a limited amount of time. Use the command "postfix reload"
to speed up a change.
The text below provides only a parameter summary. See postconf(5) for
more details including examples.
COMPATIBILITY CONTROLS
undisclosed_recipients_header (see 'postconf -d' output)
Message header that the Postfix cleanup(8) server inserts when a
message contains no To: or Cc: message header.
Available in Postfix version 2.1 only:
enable_errors_to (no)
Report mail delivery errors to the address specified with the
non-standard Errors-To: message header, instead of the envelope
sender address (this feature is removed with Postfix version
2.2, is turned off by default with Postfix version 2.1, and is
always turned on with older Postfix versions).
Available in Postfix version 2.6 and later:
always_add_missing_headers (no)
Always add (Resent-) From:, To:, Date: or Message-ID: headers
when not present.
Available in Postfix version 2.9 and later:
enable_long_queue_ids (no)
Enable long, non-repeating, queue IDs (queue file names).
Available in Postfix version 3.0 and later:
message_drop_headers (bcc, content-length, resent-bcc, return-path)
Names of message headers that the cleanup(8) daemon will remove
after applying header_checks(5) and before invoking Milter ap‐
plications.
BUILT-IN CONTENT FILTERING CONTROLS
Postfix built-in content filtering is meant to stop a flood of worms or
viruses. It is not a general content filter.
body_checks (empty)
Optional lookup tables for content inspection as specified in
the body_checks(5) manual page.
header_checks (empty)
Optional lookup tables for content inspection of primary
non-MIME message headers, as specified in the header_checks(5)
manual page.
Available in Postfix version 2.0 and later:
body_checks_size_limit (51200)
How much text in a message body segment (or attachment, if you
prefer to use that term) is subjected to body_checks inspection.
mime_header_checks ($header_checks)
Optional lookup tables for content inspection of MIME related
message headers, as described in the header_checks(5) manual
page.
nested_header_checks ($header_checks)
Optional lookup tables for content inspection of non-MIME mes‐
sage headers in attached messages, as described in the
header_checks(5) manual page.
Available in Postfix version 2.3 and later:
message_reject_characters (empty)
The set of characters that Postfix will reject in message con‐
tent.
message_strip_characters (empty)
The set of characters that Postfix will remove from message con‐
tent.
Available in Postfix version 3.9, 3.8.5, 3.7.10, 3.6.14, 3.5.24, and
later:
cleanup_replace_stray_cr_lf (yes)
Replace each stray <CR> or <LF> character in message content
with a space character, to prevent outbound SMTP smuggling, and
to make the evaluation of Postfix-added DKIM or other signatures
independent from how a remote mail server handles such charac‐
ters.
BEFORE QUEUE MILTER CONTROLS
As of version 2.3, Postfix supports the Sendmail version 8 Milter (mail
filter) protocol. When mail is not received via the smtpd(8) server,
the cleanup(8) server will simulate SMTP events to the extent that this
is possible. For details see the MILTER_README document.
non_smtpd_milters (empty)
A list of Milter (mail filter) applications for new mail that
does not arrive via the Postfix smtpd(8) server.
milter_protocol (6)
The mail filter protocol version and optional protocol exten‐
sions for communication with a Milter application; prior to
Postfix 2.6 the default protocol is 2.
milter_default_action (tempfail)
The default action when a Milter (mail filter) response is un‐
available (for example, bad Postfix configuration or Milter
failure).
milter_macro_daemon_name ($myhostname)
The {daemon_name} macro value for Milter (mail filter) applica‐
tions.
milter_macro_v ($mail_name $mail_version)
The {v} macro value for Milter (mail filter) applications.
milter_connect_timeout (30s)
The time limit for connecting to a Milter (mail filter) applica‐
tion, and for negotiating protocol options.
milter_command_timeout (30s)
The time limit for sending an SMTP command to a Milter (mail
filter) application, and for receiving the response.
milter_content_timeout (300s)
The time limit for sending message content to a Milter (mail
filter) application, and for receiving the response.
milter_connect_macros (see 'postconf -d' output)
The macros that are sent to Milter (mail filter) applications
after completion of an SMTP connection.
milter_helo_macros (see 'postconf -d' output)
The macros that are sent to Milter (mail filter) applications
after the SMTP HELO or EHLO command.
milter_mail_macros (see 'postconf -d' output)
The macros that are sent to Milter (mail filter) applications
after the SMTP MAIL FROM command.
milter_rcpt_macros (see 'postconf -d' output)
The macros that are sent to Milter (mail filter) applications
after the SMTP RCPT TO command.
milter_data_macros (see 'postconf -d' output)
The macros that are sent to version 4 or higher Milter (mail
filter) applications after the SMTP DATA command.
milter_unknown_command_macros (see 'postconf -d' output)
The macros that are sent to version 3 or higher Milter (mail
filter) applications after an unknown SMTP command.
milter_end_of_data_macros (see 'postconf -d' output)
The macros that are sent to Milter (mail filter) applications
after the message end-of-data.
Available in Postfix version 2.5 and later:
milter_end_of_header_macros (see 'postconf -d' output)
The macros that are sent to Milter (mail filter) applications
after the end of the message header.
Available in Postfix version 2.7 and later:
milter_header_checks (empty)
Optional lookup tables for content inspection of message headers
that are produced by Milter applications.
Available in Postfix version 3.1 and later:
milter_macro_defaults (empty)
Optional list of name=value pairs that specify default values
for arbitrary macros that Postfix may send to Milter applica‐
tions.
MIME PROCESSING CONTROLS
Available in Postfix version 2.0 and later:
disable_mime_input_processing (no)
Turn off MIME processing while receiving mail.
mime_boundary_length_limit (2048)
The maximal length of MIME multipart boundary strings.
mime_nesting_limit (100)
The maximal recursion level that the MIME processor will handle.
strict_8bitmime (no)
Enable both strict_7bit_headers and strict_8bitmime_body.
strict_7bit_headers (no)
Reject mail with 8-bit text in message headers.
strict_8bitmime_body (no)
Reject 8-bit message body text without 8-bit MIME content encod‐
ing information.
strict_mime_encoding_domain (no)
Reject mail with invalid Content-Transfer-Encoding: information
for the message/* or multipart/* MIME content types.
Available in Postfix version 2.5 and later:
detect_8bit_encoding_header (yes)
Automatically detect 8BITMIME body content by looking at Con‐
tent-Transfer-Encoding: message headers; historically, this be‐
havior was hard-coded to be "always on".
AUTOMATIC BCC RECIPIENT CONTROLS
Postfix can automatically add BCC (blind carbon copy) when mail enters
the mail system:
always_bcc (empty)
Optional address that receives a "blind carbon copy" of each
message that is received by the Postfix mail system.
Available in Postfix version 2.1 and later:
sender_bcc_maps (empty)
Optional BCC (blind carbon-copy) address lookup tables, indexed
by sender address.
recipient_bcc_maps (empty)
Optional BCC (blind carbon-copy) address lookup tables, indexed
by recipient address.
ADDRESS TRANSFORMATION CONTROLS
Address rewriting is delegated to the trivial-rewrite(8) daemon. The
cleanup(8) server implements table driven address mapping.
empty_address_recipient (MAILER-DAEMON)
The recipient of mail addressed to the null address.
canonical_maps (empty)
Optional address mapping lookup tables for message headers and
envelopes.
recipient_canonical_maps (empty)
Optional address mapping lookup tables for envelope and header
recipient addresses.
sender_canonical_maps (empty)
Optional address mapping lookup tables for envelope and header
sender addresses.
masquerade_classes (envelope_sender, header_sender, header_recipient)
What addresses are subject to address masquerading.
masquerade_domains (empty)
Optional list of domains whose subdomain structure will be
stripped off in email addresses.
masquerade_exceptions (empty)
Optional list of user names that are not subjected to address
masquerading, even when their addresses match $masquerade_do‐
mains.
propagate_unmatched_extensions (canonical, virtual)
What address lookup tables copy an address extension from the
lookup key to the lookup result.
Available before Postfix version 2.0:
virtual_maps (empty)
Optional lookup tables with a) names of domains for which all
addresses are aliased to addresses in other local or remote do‐
mains, and b) addresses that are aliased to addresses in other
local or remote domains.
Available in Postfix version 2.0 and later:
virtual_alias_maps ($virtual_maps)
Optional lookup tables that alias specific mail addresses or do‐
mains to other local or remote address.
Available in Postfix version 2.2 and later:
canonical_classes (envelope_sender, envelope_recipient, header_sender,
header_recipient)
What addresses are subject to canonical_maps address mapping.
recipient_canonical_classes (envelope_recipient, header_recipient)
What addresses are subject to recipient_canonical_maps address
mapping.
sender_canonical_classes (envelope_sender, header_sender)
What addresses are subject to sender_canonical_maps address map‐
ping.
remote_header_rewrite_domain (empty)
Don't rewrite message headers from remote clients at all when
this parameter is empty; otherwise, rewrite message headers and
append the specified domain name to incomplete addresses.
RESOURCE AND RATE CONTROLS
duplicate_filter_limit (1000)
The maximal number of addresses remembered by the address dupli‐
cate filter for aliases(5) or virtual(5) alias expansion, or for
showq(8) queue displays.
header_size_limit (102400)
The maximal amount of memory in bytes for storing a message
header.
hopcount_limit (50)
The maximal number of Received: message headers that is allowed
in the primary message headers.
in_flow_delay (1s)
Time to pause before accepting a new message, when the message
arrival rate exceeds the message delivery rate.
message_size_limit (10240000)
The maximal size in bytes of a message, including envelope in‐
formation.
Available in Postfix version 2.0 and later:
header_address_token_limit (10240)
The maximal number of address tokens are allowed in an address
message header.
mime_boundary_length_limit (2048)
The maximal length of MIME multipart boundary strings.
mime_nesting_limit (100)
The maximal recursion level that the MIME processor will handle.
queue_file_attribute_count_limit (100)
The maximal number of (name=value) attributes that may be stored
in a Postfix queue file.
Available in Postfix version 2.1 and later:
virtual_alias_expansion_limit (1000)
The maximal number of addresses that virtual alias expansion
produces from each original recipient.
virtual_alias_recursion_limit (1000)
The maximal nesting depth of virtual alias expansion.
Available in Postfix version 3.0 and later:
virtual_alias_address_length_limit (1000)
The maximal length of an email address after virtual alias ex‐
pansion.
SMTPUTF8 CONTROLS
Preliminary SMTPUTF8 support is introduced with Postfix 3.0.
smtputf8_enable (yes)
Enable preliminary SMTPUTF8 support for the protocols described
in RFC 6531..6533.
smtputf8_autodetect_classes (sendmail, verify)
Detect that a message requires SMTPUTF8 support for the speci‐
fied mail origin classes.
Available in Postfix version 3.2 and later:
enable_idna2003_compatibility (no)
Enable 'transitional' compatibility between IDNA2003 and
IDNA2008, when converting UTF-8 domain names to/from the ASCII
form that is used for DNS lookups.
MISCELLANEOUS CONTROLS
config_directory (see 'postconf -d' output)
The default location of the Postfix main.cf and master.cf con‐
figuration files.
daemon_timeout (18000s)
How much time a Postfix daemon process may take to handle a re‐
quest before it is terminated by a built-in watchdog timer.
delay_logging_resolution_limit (2)
The maximal number of digits after the decimal point when log‐
ging sub-second delay values.
delay_warning_time (0h)
The time after which the sender receives a copy of the message
headers of mail that is still queued.
ipc_timeout (3600s)
The time limit for sending or receiving information over an in‐
ternal communication channel.
max_idle (100s)
The maximum amount of time that an idle Postfix daemon process
waits for an incoming connection before terminating voluntarily.
max_use (100)
The maximal number of incoming connections that a Postfix daemon
process will service before terminating voluntarily.
myhostname (see 'postconf -d' output)
The internet hostname of this mail system.
myorigin ($myhostname)
The domain name that locally-posted mail appears to come from,
and that locally posted mail is delivered to.
process_id (read-only)
The process ID of a Postfix command or daemon process.
process_name (read-only)
The process name of a Postfix command or daemon process.
queue_directory (see 'postconf -d' output)
The location of the Postfix top-level queue directory.
soft_bounce (no)
Safety net to keep mail queued that would otherwise be returned
to the sender.
syslog_facility (mail)
The syslog facility of Postfix logging.
syslog_name (see 'postconf -d' output)
A prefix that is prepended to the process name in syslog
records, so that, for example, "smtpd" becomes "prefix/smtpd".
Available in Postfix version 2.1 and later:
enable_original_recipient (yes)
Enable support for the original recipient address after an ad‐
dress is rewritten to a different address (for example with
aliasing or with canonical mapping).
Available in Postfix 3.3 and later:
service_name (read-only)
The master.cf service name of a Postfix daemon process.
Available in Postfix 3.5 and later:
info_log_address_format (external)
The email address form that will be used in non-debug logging
(info, warning, etc.).
FILES
/etc/postfix/canonical*, canonical mapping table
/etc/postfix/virtual*, virtual mapping table
SEE ALSO
trivial-rewrite(8), address rewriting
qmgr(8), queue manager
header_checks(5), message header content inspection
body_checks(5), body parts content inspection
canonical(5), canonical address lookup table format
virtual(5), virtual alias lookup table format
postconf(5), configuration parameters
master(5), generic daemon options
master(8), process manager
postlogd(8), Postfix logging
syslogd(8), system logging
README FILES
ADDRESS_REWRITING_README Postfix address manipulation
CONTENT_INSPECTION_README content inspection
LICENSE
The Secure Mailer license must be distributed with this software.
AUTHOR(S)
Wietse Venema
IBM T.J. Watson Research
P.O. Box 704
Yorktown Heights, NY 10598, USA
Wietse Venema
Google, Inc.
111 8th Avenue
New York, NY 10011, USA
CLEANUP(8)