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SENDMAIL(1) General Commands Manual SENDMAIL(1)

NAME

sendmail - Postfix to Sendmail compatibility interface

SYNOPSIS

sendmail [option ...] [recipient ...]
mailq
sendmail -bp
newaliases
sendmail -I

DESCRIPTION


The Postfix sendmail(1) command implements the Postfix to Sendmail compatibility interface. For the sake of compatibility with existing applications, some Sendmail command-line options are recognized but silently ignored.

By default, Postfix sendmail(1) reads a message from standard input until EOF or until it reads a line with only a . character, and arranges for delivery. Postfix sendmail(1) relies on the postdrop(1) command to create a queue file in the maildrop directory.

Specific command aliases are provided for other common modes of operation:

List the mail queue. Each entry shows the queue file ID, message size, arrival time, sender, and the recipients that still need to be delivered. If mail could not be delivered upon the last attempt, the reason for failure is shown. The queue ID string is followed by an optional status character:
*
The message is in the active queue, i.e. the message is selected for delivery.
!
The message is in the hold queue, i.e. no further delivery attempt will be made until the mail is taken off hold.
#
The message is forced to expire. See the postsuper(1) options -e or -f.
This mode of operation is implemented by executing the postqueue(1) command.
Initialize the alias database. If no input file is specified (with the -oA option, see below), the program processes the file(s) specified with the alias_database configuration parameter. If no alias database type is specified, the program uses the type specified with the default_database_type configuration parameter. This mode of operation is implemented by running the postalias(1) command.

Note: it may take a minute or so before an alias database update becomes visible. Use the "postfix reload" command to eliminate this delay.

These and other features can be selected by specifying the appropriate combination of command-line options. Some features are controlled by parameters in the main.cf configuration file.

The following options are recognized:

Postfix sendmail uses the same configuration file regardless of whether or not a message is an initial submission.
The message body MIME type: 7BIT or 8BITMIME.
Go into daemon mode. This mode of operation is implemented by executing the "postfix start" command.
Postfix has no persistent host status database.
Initialize alias database. See the newaliases command above.
Go into daemon mode. To accept only local connections as with Sendmail's -bl option, specify "inet_interfaces = loopback" in the Postfix main.cf configuration file.
Read mail from standard input and arrange for delivery. This is the default mode of operation.
List the mail queue. See the mailq command above.
Stand-alone SMTP server mode. Read SMTP commands from standard input, and write responses to standard output. In stand-alone SMTP server mode, mail relaying and other access controls are disabled by default. To enable them, run the process as the mail_owner user.

This mode of operation is implemented by running the smtpd(8) daemon.

Do not collect or deliver a message. Instead, send an email report after verifying each recipient address. This is useful for testing address rewriting and routing configurations.

This feature is available in Postfix version 2.1 and later.

The path name of the Postfix main.cf file, or of its parent directory. This information is ignored with Postfix versions before 2.3.

With Postfix version 3.2 and later, a non-default directory must be authorized in the default main.cf file, through the alternate_config_directories or multi_instance_directories parameters.

With all Postfix versions, you can specify a directory pathname with the MAIL_CONFIG environment variable to override the location of configuration files.

Set the sender full name. This overrides the NAME environment variable, and is used only with messages that have no From: message header.
Set the envelope sender address. This is the address where delivery problems are sent to. With Postfix versions before 2.1, the Errors-To: message header overrides the error return address.
Gateway (relay) submission, as opposed to initial user submission. Either do not rewrite addresses at all, or update incomplete addresses with the domain information specified with remote_header_rewrite_domain.

This option is ignored before Postfix version 2.3.

Hop count limit. Use the hopcount_limit configuration parameter instead.
Initialize alias database. See the newaliases command above.
When reading a message from standard input, don't treat a line with only a . character as the end of input.
The logging label. Use the syslog_name configuration parameter instead.
Backwards compatibility.
Delivery status notification control. Specify either a comma-separated list with one or more of failure (send notification when delivery fails), delay (send notification when delivery is delayed), or success (send notification when the message is delivered); or specify never (don't send any notifications at all).

This feature is available in Postfix 2.3 and later.

Backwards compatibility.
Non-default alias database. Specify pathname or type:pathname. See postalias(1) for details.
Set the named option to value. Use the equivalent configuration parameter in main.cf instead.
To send 8-bit or binary content, use an appropriate MIME encapsulation and specify the appropriate -B command-line option.
When reading a message from standard input, don't treat a line with only a . character as the end of input.
The sender is never eliminated from alias etc. expansions.
Set option x to value. Use the equivalent configuration parameter in main.cf instead.
Set the envelope sender address. This is the address where delivery problems are sent to. With Postfix versions before 2.1, the Errors-To: message header overrides the error return address.
Delivery status notification control. Specify "hdrs" to return only the header when a message bounces, "full" to return a full copy (the default behavior).

The -R option specifies an upper bound; Postfix will return only the header, when a full copy would exceed the bounce_size_limit setting.

This option is ignored before Postfix version 2.10.

Attempt to deliver all queued mail. This is implemented by executing the postqueue(1) command.

Warning: flushing undeliverable mail frequently will result in poor delivery performance of all other mail.

The interval between queue runs. Use the queue_run_delay configuration parameter instead.
Schedule immediate delivery of mail with the specified queue ID. This option is implemented by executing the postqueue(1) command, and is available with Postfix version 2.4 and later.
Schedule immediate delivery of all mail that is queued for the named site. This option accepts only site names that are eligible for the "fast flush" service, and is implemented by executing the postqueue(1) command. See flush(8) for more information about the "fast flush" service.
This command is not implemented. Use the slower "sendmail -q" command instead.
Extract recipients from message headers. These are added to any recipients specified on the command line.

With Postfix versions prior to 2.1, this option requires that no recipient addresses are specified on the command line.

Initial user submission.
Specify the envelope ID for notification by servers that support DSN.

This feature is available in Postfix 2.3 and later.

Variable Envelope Return Path. Given an envelope sender address of the form owner-listname@origin, each recipient user@domain receives mail with a personalized envelope sender address.

By default, the personalized envelope sender address is owner-listname+user=domain@origin. The default + and = characters are configurable with the default_verp_delimiters configuration parameter.

As -XV, but uses x and y as the VERP delimiter characters, instead of the characters specified with the default_verp_delimiters configuration parameter.
Send an email report of the first delivery attempt (Postfix versions 2.1 and later). Mail delivery always happens in the background. When multiple -v options are given, enable verbose logging for debugging purposes.
Log mailer traffic. Use the debug_peer_list and debug_peer_level configuration parameters instead.

SECURITY



By design, this program is not set-user (or group) id. It is
    prepared to handle message content from untrusted, possibly remote,
  users.


However, like most Postfix programs, this program does not enforce
    a security policy on its command-line arguments. Instead, it relies on the
    UNIX system to enforce access policies based on the effective user and group
    IDs of the process. Concretely, this means that running Postfix commands as
    root (from sudo or equivalent) on behalf of a non-root user is likely to
    create privilege escalation opportunities.


If an application runs any Postfix programs on behalf of users
    that do not have normal shell access to Postfix commands, then that
    application MUST restrict user-specified command-line arguments to avoid
    privilege escalation.


    
  
  • Filter all command-line arguments, for example arguments that contain a
      pathname or that specify a database access method. These pathname checks
      must reject user-controlled symlinks or hardlinks to sensitive files, and
      must not be vulnerable to TOCTOU race attacks.
    • 
  
  • Disable command options processing for all command arguments that contain
      user-specified data. For example, the Postfix sendmail(1) command
      line MUST be structured as follows:
    
    
    

    
    /path/to/sendmail system-arguments -- user-arguments
    
    
    Here, the "--" disables command option
        processing for all user-arguments that follow.
    
  
    • 




  

  
Without the "--", a malicious user could enable Postfix
      sendmail(1) command options, by specifying an email address that
      starts with "-".








DIAGNOSTICS




Problems are logged to syslogd(8) or postlogd(8),
    and to the standard error stream.






ENVIRONMENT





  

  
Directory with Postfix configuration files.

  

  
Enable verbose logging for debugging purposes.

  

  
Enable debugging with an external command, as specified with the
      debugger_command configuration parameter.

  
NAME

  
The sender full name. This is used only with messages that have no
      From: message header. See also the -F option above.








CONFIGURATION PARAMETERS




The following main.cf parameters are especially relevant to
    this program. The text below provides only a parameter summary. See
    postconf(5) for more details including examples.






COMPATIBILITY CONTROLS




Available with Postfix 2.9 and later:



  

  
Controls how the Postfix sendmail command converts email message line
      endings from <CR><LF> into UNIX format (<LF>).








TROUBLE SHOOTING CONTROLS




The DEBUG_README file gives examples of how to troubleshoot a
    Postfix system.



  

  
The external command to execute when a Postfix daemon program is invoked
      with the -D option.

  

  
The increment in verbose logging level when a nexthop destination, remote
      client or server name or network address matches a pattern given with the
      debug_peer_list parameter.

  

  
Optional list of nexthop destination, remote client or server name or
      network address patterns that, if matched, cause the verbose logging level
      to increase by the amount specified in $debug_peer_level.








ACCESS CONTROLS




Available in Postfix version 2.2 and later:



  

  
List of users who are authorized to flush the queue.

  

  
List of users who are authorized to view the queue.

  

  
List of users who are authorized to submit mail with the
      sendmail(1) command (and with the privileged postdrop(1)
      helper command).








RESOURCE AND RATE CONTROLS





  

  
The maximal amount of original message text that is sent in a non-delivery
      notification.

  

  
The maximal number of attempts to fork() a child process.

  

  
The delay between attempts to fork() a child process.

  

  
The maximal number of Received: message headers that is allowed in the
      primary message headers.

  

  
The time between deferred queue scans by the queue manager; prior to
      Postfix 2.4 the default value was 1000s.








FAST FLUSH CONTROLS




The ETRN_README file describes configuration and operation details
    for the Postfix "fast flush" service.



  

  
Optional list of destinations that are eligible for per-destination
      logfiles with mail that is queued to those destinations.








VERP CONTROLS




The VERP_README file describes configuration and operation details
    of Postfix support for variable envelope return path addresses.



  

  
The two default VERP delimiter characters.

  

  
The characters Postfix accepts as VERP delimiter characters on the Postfix
      sendmail(1) command line and in SMTP commands.








MISCELLANEOUS CONTROLS





  

  
The alias databases for local(8) delivery that are updated with
      "newaliases" or with "sendmail
    -bi".

  

  
The location of all postfix administrative commands.

  

  
The default location of the Postfix main.cf and master.cf configuration
      files.

  

  
The directory with Postfix support programs and daemon programs.

  

  
The default database type for use in newaliases(1),
      postalias(1) and postmap(1) commands.

  

  
The time after which the sender receives a copy of the message headers of
      mail that is still queued.

  

  
The list of environment variables that a privileged Postfix process will
      import from a non-Postfix parent process, or name=value environment
      overrides.

  

  
The UNIX system account that owns the Postfix queue and most Postfix
      daemon processes.

  

  
The location of the Postfix top-level queue directory.

  

  
Rewrite or add message headers in mail from remote clients if the
      remote_header_rewrite_domain parameter value is non-empty, updating
      incomplete addresses with the domain specified in the
      remote_header_rewrite_domain parameter, and adding missing headers.

  

  
The syslog facility of Postfix logging.

  

  
A prefix that is prepended to the process name in syslog records, so that,
      for example, "smtpd" becomes "prefix/smtpd".




Postfix 3.2 and later:



  

  
A list of non-default Postfix configuration directories that may be
      specified with "-c config_directory" on the command line (in the
      case of sendmail(1), with the "-C" option), or via the
      MAIL_CONFIG environment parameter.

  

  
An optional list of non-default Postfix configuration directories; these
      directories belong to additional Postfix instances that share the Postfix
      executable files and documentation with the default Postfix instance, and
      that are started, stopped, etc., together with the default Postfix
      instance.








FILES


/var/spool/postfix, mail queue
/etc/postfix, configuration files






SEE ALSO


pickup(8), mail pickup daemon
qmgr(8), queue manager
smtpd(8), SMTP server
flush(8), fast flush service
postsuper(1), queue maintenance
postalias(1), create/update/query alias database
postdrop(1), mail posting utility
postfix(1), mail system control
postqueue(1), mail queue control
postlogd(8), Postfix logging
syslogd(8), system logging






README_FILES




Use "postconf readme_directory" or
    "postconf html_directory" to locate this information.


DEBUG_README, Postfix debugging howto
ETRN_README, Postfix ETRN howto
VERP_README, Postfix VERP howto






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