This is msmtp.info, produced by makeinfo version 6.1 from msmtp.texi.

This manual was last updated 9 April 2016 for version 1.6.5 of msmtp.

   Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013,
2014, 2015, 2016 Martin Lambers
Copyright (C) 2011 Scott Shumate

     Copying and distribution of this file, with or without
     modification, are permitted in any medium without royalty provided
     the copyright notice and this notice are preserved.  These files
     are offered as-is, without any warranty.
INFO-DIR-SECTION Individual utilities
START-INFO-DIR-ENTRY
* msmtp: (msmtp).	An SMTP client.
END-INFO-DIR-ENTRY


File: msmtp.info,  Node: Top,  Next: Introduction,  Up: (dir)

msmtp
*****

This manual was last updated 9 April 2016 for version 1.6.5 of msmtp.

   Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013,
2014, 2015, 2016 Martin Lambers
Copyright (C) 2011 Scott Shumate

     Copying and distribution of this file, with or without
     modification, are permitted in any medium without royalty provided
     the copyright notice and this notice are preserved.  These files
     are offered as-is, without any warranty.

* Menu:

* Introduction::			Basic concepts.
* Configuration files::			Configuration file commands.
* Invocation::				Command line options.
* Transport Layer Security::		How to use TLS/SSL.
* Authentication::			How to use authentication.
* Delivery Status Notifications::	How to use DSN.
* Sendmail mode::			How to send mail.
* Server information mode::		How to obtain information about
					an SMTP server.
* Remote Message Queue Starting mode::	How to send RMQS requests.
* Examples::				Usage examples.


File: msmtp.info,  Node: Introduction,  Next: Configuration files,  Prev: Top,  Up: Top

1 Introduction
**************

msmtp is an SMTP client.

   In its default mode of operation, it reads a mail from standard input
and sends it to a predefined SMTP server that takes care of proper
delivery.  Command line options and exit codes are compatible to
sendmail.

   The best way to start is probably to have a look at the Examples
section.  *Note Examples::.

   In addition to sendmail mode, there are two other modes of operation:
   • Server information mode.  In this mode, msmtp prints as much
     information as it can get about a given SMTP server (supported
     features, maximum mail size, ...).
   • Remote Message Queue Starting mode.  In this mode, msmtp sends a
     Remote Message Queue Starting request for a host, domain, or queue
     to a given SMTP server.

   Normally, a system wide configuration file and/or a user
configuration file contain information about which SMTP server to use
and how to use it, but all settings can also be configured on the
command line.

   The information about SMTP servers is organized in accounts.  Each
account describes one SMTP server: host name, authentication settings,
TLS settings, and so on.  Each configuration file can define multiple
accounts.

   Supported features include:
   • TLS secured connections (including server certificate verification
     and the possibility to send a client certificate)
   • Authentication methods PLAIN, LOGIN, CRAM-MD5 and EXTERNAL (and
     GSSAPI, SCRAM-SHA-1, DIGEST-MD5, and NTLM when compiled with GNU
     SASL support)
   • Internationalized Domain Names (IDN)
   • DSN (Delivery Status Notification) support
   • PIPELINING support for increased transmission speed
   • RMQS (Remote Message Queue Starting) support (ETRN keyword)


File: msmtp.info,  Node: Configuration files,  Next: Invocation,  Prev: Introduction,  Up: Top

2 Configuration files
*********************

msmtp supports a system wide configuration file and a user configuration
file.  Both are optional and need not exist.

   If it exists and is readable, a system wide configuration file
‘SYSCONFDIR/msmtprc’ will be loaded.  Use ‘--version’ to find out which
‘SYSCONFDIR’ your version of msmtp uses.

   The default user configuration file is ‘~/.msmtprc’.  Accounts
defined in the user configuration file override accounts from the system
configuration file.  Configuration file settings can be changed by
command line options.

   A configuration file is a simple text file.  Empty lines and comment
lines (first non-blank character is ’#’) are ignored.  Every other line
must contain a command and may contain an argument to that command.  The
argument may be enclosed in double quotes (").

   If a file name starts with the tilde (~), this tilde will be replaced
by ‘$HOME’.

   If a command accepts the argument ‘on’, it also accepts an empty
argument and treats that as if it was ‘on’.

   Commands are organized in accounts.  Each account starts with the
‘account’ command and defines the settings for one SMTP account.

   *Note Examples::.

2.1 General commands
====================

‘defaults’
     Set defaults.  The following commands will set default values for
     all following account definitions in the current configuration
     file.
‘account NAME [: ACCOUNT[,...]]’
     Start a new account definition with the given name.  The current
     default values are filled in (see *note defaults::).
     If a colon and a list of previously defined accounts is given after
     the account name, the new account, with the filled in default
     values, will inherit all settings from the accounts in the list.
‘host HOSTNAME’
     The SMTP server to send the mail to.  The argument may be a host
     name or a network address.  Every account definition must contain
     this command.
‘port NUMBER’
     The port that the SMTP server listens on.  The default is 25
     ("smtp"), unless TLS without STARTTLS is used, in which case it is
     465 ("smtps").
‘timeout (off|SECONDS)’
     Set or unset a network timeout, in seconds.  The argument ‘off’
     means that no timeout will be set, which means that the operating
     system default will be used.
‘proxy_host [IP|HOSTNAME]’
     Use a SOCKS proxy.  All network traffic will go through this proxy
     host, including DNS queries, except for a DNS query that might be
     necessary to resolve the proxy host name itself (this can be
     avoided by using an IP address as proxy host name).  An empty
     argument disables proxy usage.  The supported SOCKS protocol
     version is 5.  If you plan to use this with Tor, see also *note
     Using msmtp with Tor::.
‘proxy_port [NUMBER]’
     Set the port number for the proxy host.  An empty ‘number’ argument
     resets this to the default port, which is 1080 ("socks").
‘protocol (smtp|lmtp)’
     Set the protocol to use.  Currently only SMTP and LMTP are
     supported.  SMTP is the default.  See *note port:: for default
     ports.
‘domain ARGUMENT’
     This command sets the argument of the SMTP EHLO (or LMTP LHLO)
     command.  The default is ‘localhost’, which is stupid but usually
     works.  Try to change the default if mails get rejected due to
     anti-SPAM measures.  Possible choices are the domain part of your
     mail address (‘provider.example’ for ‘joe@provider.example’) or the
     fully qualified domain name of your host (if available).

2.2 Authentication commands
===========================

*Note Authentication::.

‘auth [(on|off|METHOD)]’
     Enable or disable authentication and optionally choose a method to
     use.  The argument ‘on’ chooses a method automatically.  Accepted
     methods are ‘plain’, ‘scram-sha-1’, ‘cram-md5’, ‘gssapi’,
     ‘external’, ‘digest-md5’, ‘login’, and ‘ntlm’.  *Note
     Authentication::.
‘user [USERNAME]’
     Set the user name for authentication.  An empty argument unsets the
     user name.  Authentication must be activated with the ‘auth’
     command.
‘password [SECRET]’
     Set the password for authentication.  An empty argument unsets the
     password.  Consider using the ‘passwordeval’ command or a key ring
     instead of this command, to avoid storing plain text passwords in
     the configuration file.  *Note Authentication::.
‘passwordeval [EVAL]’
     Set the password for authentication to the output (stdout) of the
     command EVAL.  This can be used e.g.  to decrypt password files on
     the fly or to query key rings, and thus to avoid storing plain text
     passwords.  *Note Authentication::.
‘ntlmdomain [NTLMDOMAIN]’
     Set a domain for the ‘ntlm’ authentication method.  This is
     obsolete.

2.3 TLS commands
================

*Note Transport Layer Security::.

‘tls [(on|off)]’
     Enable or disable TLS (also known as SSL) for secured connections.
     You also need ‘tls_trust_file’ or ‘tls_fingerprint’, and for some
     servers you may need to disable ‘tls_starttls’.
‘tls_starttls [(on|off)]’
     Choose the TLS variant: start TLS from within the session (‘on’,
     default), or tunnel the session through TLS (‘off’).
‘tls_trust_file [FILE]’
     Activate server certificate verification using a list of truted
     Certification Authorities (CAs).  The file must be in PEM format.
     Some systems provide a system-wide default file, e.g.
     ‘/etc/ssl/certs/ca-certificates.crt’ on Debian-based systems with
     the ‘ca-certificates’ package.  An empty argument disables this.
     You should also use ‘tls_crl_file’.
‘tls_crl_file [FILE]’
     Set a certificate revocation list (CRL) file for TLS, to check for
     revoked certificates.  An empty argument disables this.
‘tls_fingerprint [FINGERPRINT]’
     Set the fingerprint of a single certificate to accept for TLS. This
     certificate will be trusted regardless of its contents.  The
     fingerprint should be of type SHA256, but can for backwards
     compatibility also be of type SHA1 or MD5 (please avoid this).  The
     format should be ‘01:23:45:67:...’.  Use ‘--serverinfo --tls
     --tls-certcheck=off --tls-fingerprint=’ to get the server
     certificate fingerprint.
‘tls_key_file [FILE]’
     Send a client certificate to the server (use this together with
     ‘tls_cert_file’).  The file must contain the private key of a
     certificate in PEM format.  An empty argument disables this
     feature.
‘tls_cert_file [FILE]’
     Send a client certificate to the server (use this together with
     ‘tls_key_file’).  The file must contain a certificate in PEM
     format.  An empty argument disables this feature.
‘tls_certcheck [(on|off)]’
     Enable or disable checks of the server certificate.
     WARNING: When the checks are disabled, TLS sessions will be
     vulnerable to man-in-the-middle attacks!
‘tls_min_dh_prime_bits [BITS]’
     Set or unset the minimum number of Diffie-Hellman (DH) prime bits
     accepted for TLS sessions.  The default is set by the TLS library
     and can be selected by using an empty argument to this command.
     Only lower the default (for example to 512 bits) if there is no
     other way to make TLS work with the remote server.
‘tls_priorities [PRIORITIES]’
     Set the priorities for TLS sessions.  The default is set by the TLS
     library and can be selected by using an empty argument to this
     command.  See the GnuTLS documentation of the
     ‘gnutls_priority_init’ function for a description of the PRIORITIES
     string.

2.4 Commands specific to sendmail mode
======================================

*Note Sendmail mode::.

‘from [ADDRESS]’
     Set the envelope-from address.  This is usually required, but
     sometimes ‘auto_from’ is a useful alternative.  *Note Envelope-from
     address::.
‘auto_from [(on|off)]’
     Enable or disable automatic envelope-from addresses.  The default
     is ‘off’.  When enabled, an envelope-from address of the form
     user@domain will be generated.  The local part will be set to
     ‘USER’ or, if that fails, to ‘LOGNAME’ or, if that fails, to the
     login name of the current user.  The domain part can be set with
     the ‘maildomain’ command; if that is empty, the address not have a
     domain part.  *Note Envelope-from address::.
‘maildomain [DOMAIN]’
     Set a domain part for the generation of an envelope-from address.
     See *note auto_from::.
‘dsn_notify (off|CONDITION)’
     Set the condition(s) under which the mail system should send DSN
     (Delivery Status Notification) messages.  The argument ‘off’
     disables explicit DSN requests, which means the mail system decides
     when to send DSN messages.  This is the default.  The CONDITION
     must be ‘never’, to never request notification, or a comma
     separated list (no spaces!)  of one or more of the following:
     ‘failure’, to request notification on transmission failure,
     ‘delay’, to be notified of message delays, ‘success’, to be
     notified of successful transmission.  The SMTP server must support
     the DSN extension.  *Note Delivery Status Notifications::.
‘dsn_return (off|AMOUNT)’
     This command controls how much of a mail should be returned in DSN
     (Delivery Status Notification) messages.  The argument ‘off’
     disables explicit DSN requests, which means the mail system decides
     how much of a mail it returns in DSN messages.  This is the
     default.  The AMOUNT must be ‘headers’, to just return the message
     headers, or ‘full’, to return the full mail.  The SMTP server must
     support the DSN extension.  *Note Delivery Status Notifications::.
‘add_missing_from_header [(on|off)]’
     This command controls whether to add a From header if the mail does
     not have one.  The default is to add it.  *Note Header handling::.
‘add_missing_date_header [(on|off)]’
     This command controls whether to add a Date header if the mail does
     not have one.  The default is to add it.  *Note Header handling::.
‘remove_bcc_headers [(on|off)]’
     This command controls whether to remove Bcc headers.  The default
     is to remove them.  *Note Header handling::.
‘logfile [FILE]’
     Enable logging to the specified file.  An empty argument disables
     logging.  The file name ‘-’ directs the log information to standard
     output.  *Note Logging::.
‘syslog [(on|off|FACILITY)]’
     Enable or disable syslog logging.  The FACILITY can be one of
     ‘LOG_USER’, ‘LOG_MAIL’, ‘LOG_LOCAL0’, ..., ‘LOG_LOCAL7’.  The
     default is ‘LOG_USER’.  Syslog logging is disabled by default.
     *Note Logging::.
‘aliases [FILE]’
     Replace local recipients with addresses in the aliases file.  The
     aliases file is a plain text file containing mappings between a
     local address and a list of domain addresses.  A local address is
     defined as one without an ’@’ character and a domain address is one
     with an ’@’ character.  The mappings are of the form:
          local: someone@example.com, person@domain.example
     Multiple domain addresses are separated with commas.  Comments
     start with ’#’ and continue to the end of the line.
     The local address ‘default’ has special significance and is matched
     if the local address is not found in the aliases file.  If no
     ‘default’ alias is found, then the local address is left as is.
     An empty argument to the aliases command disables the replacement
     of local addresses.  This is the default.


File: msmtp.info,  Node: Invocation,  Next: Transport Layer Security,  Prev: Configuration files,  Up: Top

3 Invocation
************

3.1 Synopsis
============

   • Sendmail mode (default):
     ‘msmtp [OPTION...] [--] RECIPIENT...’
     ‘msmtp [OPTION...] -t [--] [RECIPIENT...]’
   • Server information mode:
     ‘msmtp [OPTION...] --serverinfo’
   • Remote Message Queue Starting mode:
     ‘msmtp [OPTION...] --rmqs=(HOST|@DOMAIN|#QUEUE)’

3.2 Options
===========

Options override configuration file settings.  They are compatible with
sendmail where appropriate.

3.2.1 General options
---------------------

‘--version’
     Print version information, including information about the
     libraries used.
‘--help’
     Print help.
‘-P’
‘--pretend’
     Print the configuration settings that would be used, but do not
     take further action.  An asterisk (’*’) will be printed instead of
     the password.
‘-v’
‘-d’
‘--debug’
     Print lots of debugging information, including the whole
     conversation with the server.  Be careful with this option: the
     (potentially dangerous) output will not be sanitized, and your
     password may get printed in an easily decodable format!

3.2.2 Changing the mode of operation
------------------------------------

‘-S’
‘--serverinfo’
     Print information about the SMTP server and exit.  This includes
     information about supported features (mail size limit,
     authentication, TLS, DSN, ...) and about the TLS certificate (if
     TLS is active).  *Note Server information mode::.
‘--rmqs=(HOST|@DOMAIN|#QUEUE)’
     Send a Remote Message Queue Starting request for the given host,
     domain, or queue to the SMTP server and exit.  *Note Remote Message
     Queue Starting mode::.

3.2.3 Configuration options
---------------------------

Most options in this category correspond to a configuration file
command.  Please refer to *note Configuration files:: for detailed
information.
‘-C FILENAME’
‘--file=FILENAME’
     Use the given file instead of ‘~/.msmtprc’ as the user
     configuration file.
‘-a ACCOUNT’
‘--account=ACCOUNT’
     Use the given account instead of the account named ‘default’.  This
     option cannot be used together with the ‘--host’ option.  *Note
     Choosing an account::.
‘--host=HOSTNAME’
     Use this server with settings from the command line; do not use any
     configuration file data.  This option cannot be used together with
     the ‘--account’ option.  It disables loading of configuration
     files.  *Note Choosing an account::.
‘--port=NUMBER’
     Set the port number to connect to.  *Note port::.
‘--timeout=(off|SECONDS)’
     Set or unset a network timeout, in seconds.  *Note timeout::.
‘--protocol=(smtp|lmtp)’
     Set or unset a SOCKS proxy to use.  *Note proxy_host::.
‘--proxy-port=[NUMBER]’
     Set or unset a port number for the proxy host.  *Note proxy_port::.
     Set the protocol.  *Note protocol::.
‘--domain=[ARGUMENT]’
     Set the argument of the SMTP EHLO (or LMTP LHLO) command.  *Note
     domain::.
‘--proxy-host=[IP|HOSTNAME]’
‘--auth[=(on|off|METHOD)]’
     Enable or disable authentication and optionally choose the method.
     *Note auth::.
‘--user=[USERNAME]’
     Set or unset the user name for authentication.  *Note user::.
‘--passwordeval=[EVAL]’
     Evaluate password for authentication.  *Note passwordeval::.
‘--tls[=(on|off)]’
     Enable or disable TLS/SSL. *Note tls::.
‘--tls-starttls[=(on|off)]’
     Enable or disable STARTTLS for TLS. *Note tls_starttls::.
‘--tls-trust-file=[FILE]’
     Set or unset a trust file for TLS. *Note tls_trust_file::.
‘--tls-crl-file=[FILE]’
     Set or unset a certificate revocation list (CRL) file for TLS.
     *Note tls_crl_file::.
‘--tls-fingerprint=[FINGERPRINT]’
     Set ot unset the fingerprint of a trusted TLS certificate.  *Note
     tls_fingerprint::.
‘--tls-key-file=[FILE]’
     Set or unset a key file for TLS. *Note tls_key_file::.
‘--tls-cert-file=[FILE]’
     Set or unset a cert file for TLS. *Note tls_cert_file::.
‘--tls-certcheck[=(on|off)]’
     Enable or disable server certificate checks for TLS. *Note
     tls_certcheck::.
‘--tls-min-dh-prime-bits=[BITS]’
     Set or unset minimum bit size of the Diffie-Hellman (DH) prime.
     *Note tls_min_dh_prime_bits::.
‘--tls-priorities=[PRIORITIES]’
     Set or unset TLS priorities.  *Note tls_priorities::.

3.2.4 Options specific to sendmail mode
---------------------------------------

‘-f ADDRESS’
‘--from=ADDRESS’
     Set the envelope-from address.  *Note from::.
     If no account was chosen yet (with ‘--account’ or ‘--host’), this
     option will choose the first account that has the given
     envelope-from address (set with the ‘from’ command).  If no such
     account is found, "default" is used.  *Note Choosing an account::.
‘--auto-from[=(on|off)]’
     Enable or disable automatic envelope-from addresses.  *Note
     auto_from::.
‘--maildomain=[DOMAIN]’
     Set the domain part for the ‘--auto-from’ address.  *Note
     maildomain::.
‘-N (off|CONDITION)’
‘--dsn-notify=(off|CONDITION)’
     Set or unset DSN notification conditions.  *Note dsn_notify::.
‘-R (off|AMOUNT)’
‘--dsn-return=(off|AMOUNT)’
     Set or unset the DSN notification amount.  *Note dsn_return::.
     Note that ‘hdrs’ is accepted as an alias for ‘headers’ to be
     compatible with sendmail.
‘--add-missing-from-header[=(on|off)]’
     Enable or disable the addition of a missing From header.  *Note
     add_missing_from_header::.
‘--add-missing-date-header[=(on|off)]’
     Enable or disable the addition of a missing Date header.  *Note
     add_missing_date_header::.
‘--remove-bcc-headers[=(on|off)]’
     Enable or disable the removal of Bcc headers.  *Note
     remove_bcc_headers::.
‘-X [FILE]’
‘--logfile=[FILE]’
     Set or unset the log file.  *Note logfile::.
‘--syslog[=(on|off|FACILITY)]’
     Enable or disable syslog logging.  *Note syslog::.
‘-t’
‘--read-recipients’
     Send the mail to the recipients given in the To, Cc, and Bcc
     headers of the mail in addition to the recipients given on the
     command line.
     If any Resent- headers are present, then the addresses from any
     Resent-To, Resent-Cc, and Resent-Bcc headers in the first block of
     Resent- headers are used instead.
‘--read-envelope-from’
     Read the envelope from address from the From header of the mail.
     Currently this header must be on a single line for this option to
     work correctly.
‘--aliases=[FILE]’
     Set or unset an aliases file.  *Note aliases::.
‘-FNAME’
     Msmtp adds a From header to mails that lack it, using the envelope
     from address.  This option allows to set a full name to be used in
     that header.
‘--’
     This marks the end of options.  All following arguments will be
     treated as recipient addresses, even if they start with a ’-’.

   The following options are accepted but ignored for sendmail
compatibility: ‘-BTYPE’, ‘-bm’, ‘-G’, ‘-hN’, ‘-i’, ‘-L TAG’, ‘-m’, ‘-n’,
‘-O option=VALUE’, ‘-ox VALUE’

3.3 Choosing an account
=======================

There are three ways to choose the account to use.

  1. ‘--account=ACCOUNT’
     Use the given account.  Command line settings override
     configuration file settings.
  2. ‘--host=HOSTNAME’
     Use only the settings from the command line; do not use any
     configuration file data.
  3. ‘--from=ADDRESS’ or ‘--read-envelope-from’
     Choose the first account from the system or user configuration file
     that has a matching envelope-from address as specified by a *note
     from:: command.  This works only when neither ‘--account’ nor
     ‘--host’ is used.
   If none of the above options is used (or if no account has a matching
*note from:: command), then the account "default" is used.

3.4 Exit code
=============

The standard exit codes from ‘sysexits.h’ are used.

3.5 Files
=========

‘‘SYSCONFDIR/msmtprc’’
     The system configuration file.  Use the ‘--version’ option to find
     out what ‘SYSCONFDIR’ is on your platform.
‘‘~/.msmtprc’’
     The default user configuration file.
‘‘~/.netrc’ and ‘SYSCONFDIR/netrc’’
     The ‘netrc’ file contains login information.  Before prompting for
     a password, msmtp will search it in ~/.netrc and SYSCONFDIR/netrc.

3.6 Environment
===============

‘‘USER’, ‘LOGNAME’’
     These variables override the user’s login name when constructing an
     envelope-from address.  ‘LOGNAME’ is only used if ‘USER’ is unset.
‘‘TMPDIR’’
     Directory to create temporary files in.  If this is unset, a system
     specific default directory is used.  A temporary file is used to
     buffer the headers of the mail but not the mail body, so the file
     will not get very large.
‘‘EMAIL’, ‘SMTPSERVER’’
     These environment variables are used only if neither ‘--host’ nor
     ‘--account’ is used and there is no default account defined in the
     configuration files.  In this case, the host name is taken from
     ‘SMTPSERVER’, and the envelope from address is taken from ‘EMAIL’,
     unless overridden by ‘--from’ or ‘--read-envelope-from’.  Currently
     ‘SMTPSERVER’ must contain a plain host name (no URL), and ‘EMAIL’
     must contain a plain address (no names or additional information).


File: msmtp.info,  Node: Transport Layer Security,  Next: Authentication,  Prev: Invocation,  Up: Top

4 Transport Layer Security
**************************

Transport Layer Security (TLS) "... provides communications privacy over
the Internet.  The protocol allows client/server applications to
communicate in a way that is designed to prevent eavesdropping,
tampering, or message forgery" (quote from RFC2246).

   A server can use TLS in one of two modes:
   • Via a STARTTLS command
     The session starts with the normal protocol initialization, and TLS
     is then started using the protocol’s STARTTLS command.
   • Immediately
     TLS is initialized before the normal protocol initialization.  This
     requires a separate port.
   The first mode is the default, but you can switch to the second mode
by disabling *note tls_starttls::.

   When TLS is started, the server sends a certificate to identify
itself.  To verify the server identity, a client program is expected to
check that the certificate is formally correct and that it was issued by
a Certificate Authority (CA) that the user trusts.  (There can also be
certificate chains with intermediate CAs.)

   The list of trusted CAs is specified using the *note tls_trust_file::
command.  Usually there is some system-wide default file available, e.g.
‘/etc/ssl/certs/ca-certificates.crt’ on Debian-based systems, but you
can also choose to select the trusted CAs yourself.

   One practical problem with this approach is that the client program
should also check if the server certificate has been revoked for some
reason, using a Certificate Revocation List (CRL). A CRL file can be
specified using the *note tls_crl_file:: command, but getting the
relevant CRL files and keeping them up to date is not straightforward.
You are basically on your own.

   A much more serious and fundamental problem is is that you need to
trust CAs.  Like any other organization, a CA can be incompetent,
malicious, subverted by bad people, or forced by government agencies to
compromise end users without telling them.  All of these things happened
and continue to happen worldwide.  The idea to have central
organizations that have to be trusted for your communication to be
secure is fundamentally broken.

   Instead of putting trust in a CA, you can choose to trust only a
single certificate for the server you want to connect to.  For that
purpose, specify the certificate fingerprint with *note
tls_fingerprint::.  This makes sure that no man-in-the-middle can fake
the identity of the server by presenting you a fraudulent certificate
issued by some CA that happens to be in your trust list.  However, you
have to update the fingerprint whenever the server certificate changes,
and you have to make sure that the change is legitimate each time, e.g.
when the old certificate expired.  This is inconvenient, but it’s the
price to pay.

   Information about a server certificate can be obtained with
‘--serverinfo --tls --tls-certcheck=off’.  This includes the issuer CA
of the certificate (so you can trust that CA via ‘tls_trust_file’), and
the fingerprint of the certificate (so you can trust that particular
certificate via ‘tls_fingerprint’).  *Note Server information mode::.

   TLS also allows the server to verify the identity of the client.  For
this purpose, the client has to present a certificate issued by a CA
that the server trusts.  To present that certificate, the client also
needs the matching key file.  You can set the certificate and key files
using *note tls_cert_file:: and *note tls_key_file::.  This mechanism
can also be used to authenticate users, so that traditional user /
password authentication is not necessary anymore.  See the EXTERNAL
mechanism in *note Authentication::.

   If you need to fine tune TLS parameters, have a look at the *note
tls_priorities:: and *note tls_min_dh_prime_bits:: commands.


File: msmtp.info,  Node: Authentication,  Next: Delivery Status Notifications,  Prev: Transport Layer Security,  Up: Top

5 Authentication
****************

Many SMTP servers require a client to authenticate before sending mail.

   Usually a user name and a password are used for authentication.  The
user name specified in the configuration file with the *note user::
command.  There are five different methods to specify the password:
  1. Add the password to the system key ring.
     Currently supported key rings are the Gnome key ring and the Mac OS
     X Keychain.  For the Gnome key ring, use the command ‘secret-tool’
     (part of Gnome’s libsecret) to store passwords:
          $ secret-tool store --label=msmtp \
            host mail.freemail.example \
            service smtp \
            user joe.smith
     On Mac OS X, use the Keychain Access GUI application.  The ‘account
     name’ is same as the user name.  The ‘keychain item name’ is
     ‘smtp://<hostname>’ where ‘<hostname>’ matches the ‘host’ argument.
  2. Store the password in an encrypted files, and use *note
     passwordeval:: to specify a command to decrypt that file, e.g.
     using GnuPG. *Note Examples::.
  3. Store the password in the configuration file using the *note
     password:: command.  (Usually it is not considered a good idea to
     store passwords in plain text files.  If you do it anyway, you must
     make sure that the file can only be read by yourself.)
  4. Store the password in ‘~/.netrc’.  This method is probably
     obsolete.
  5. Type the password into the terminal when it is required.
   It is recommended to use method 1 or 2.

   Multiple authentication methods exist.  Most servers support only
some of them.  Historically, sophisticated methods were developed to
protect passwords from being sent unencrypted to the server, but
nowadays everybody needs *note Transport Layer Security:: anyway, so the
simple methods suffice since the whole session is protected.  A suitable
authentication method is chosen automatically, and when TLS is disabled
for some reason, only methods that avoid sending clear text passwords
are considered.

   The following user / password methods are supported:
   • ‘PLAIN’
     Another simple plain text method (with base64 encoding) support by
     almost all servers.
   • ‘SCRAM-SHA-1’
     A method that avoids clear-text passwords.
   • ‘CRAM-MD5’
     An obsolete method that avoids clear-text passwords.
   • ‘DIGEST-MD5’
     An overcomplicated obsolete method that avoids clear-text
     passwords, but is not considered secure anymore.
   • ‘LOGIN’
     A non-standard clear-text method similar to (but worse than) PLAIN.
   • ‘NTLM’
     An obscure non-standard method that is now considered broken.  It
     sometimes requires a special domain parameter passed via *note
     ntlmdomain::.  Do not use it.

   There are currently two authentication methods that are not based on
user / password information and have to be chosen manually:
   • ‘EXTERNAL’
     The authentication happens outside of the protocol, typically by
     sending a TLS client certificate (see *note Transport Layer
     Security::).
     The EXTERNAL method merely confirms that this authentication
     succeeded; it does not perform the authentication.  Thus it may not
     be necessary to use it for authentication to succeed, and if the
     server does not support the EXTERNAL method, this does not mean
     that it does not support authentication with TLS client
     certificates.
   • ‘GSSAPI’
     With this method, the Kerberos framework takes care of secure
     authentication.  Only a user name is required.

   It depends on the underlying authentication library and its version
whether a particular method is supported or not.  Use ‘--version’ to
find out which methods are supported by your version.


File: msmtp.info,  Node: Delivery Status Notifications,  Next: Sendmail mode,  Prev: Authentication,  Up: Top

6 Delivery Status Notifications
*******************************

In situations such as delivery failure or delay, the mail system usually
generates a message for the sender of the mail, informing him about the
difficulties.

   Delivery Status Notification (DSN) requests, defined in RFC 3461, try
to give the sender of the mail control about how and when these DSN
messages are sent.  The SMTP server must support the DSN extension.
*Note Server information mode::.

   A first parameter controls when such messages should be generated:
never, on delivery failure, on delivery delay, and/or on success.  This
can be set with *note dsn_notify:: and *note --dsn-notify::.

   A second parameter controls how much of the original mail should be
contained in a DSN message: only the headers, or the full mail.  This
can be set with *note dsn_return:: and *note --dsn-return::.  Note that
this parameter only applies to DSNs that indicate delivery failure for
at least one recipient.  If a DSN contains no indications of delivery
failure, only the headers of the message are returned.


File: msmtp.info,  Node: Sendmail mode,  Next: Server information mode,  Prev: Delivery Status Notifications,  Up: Top

7 Sendmail mode
***************

* Menu:

* Envelope-from address::	Information about envelope-from addresses
* Logging::			Different logging methods
* Header handling::		Modifications to mail headers


File: msmtp.info,  Node: Envelope-from address,  Next: Logging,  Up: Sendmail mode

7.1 Envelope-from address
=========================

The SMTP server expects a sender mail address for each mail.  This is
the envelope-from address.  It is independent of the From header
(because it is part of the mail _envelope_, not of the mail itself), but
in most cases both addresses are the same.

   Envelope-from addresses can be generated automatically (when *note
auto_from:: is enabled) or set explicitly with the *note from:: command.


File: msmtp.info,  Node: Logging,  Next: Header handling,  Prev: Envelope-from address,  Up: Sendmail mode

7.2 Logging
===========

When logging is enabled, msmtp will generate one log line for each mail
it tries to send.

   The line will include the following information:
   • Host name of the SMTP server: ‘host=hostname’
   • Whether TLS was used: ‘tls=(on|off)’
   • Whether authentication was used: ‘auth=(on|off)’
   • The user name used for authentication (only if authentication is
     used): ‘user=name’
   • The envelope-from address: ‘from=address’
   • The recipient addresses: ‘recipients=addr1,addr2,...’
   • The size of the mail as transferred to the server, in bytes (only
     if the delivery succeeded): ‘mailsize=number’
   • The SMTP status code and SMTP error message (only in case of
     failure and only if available): ‘smtpstatus=number’,
     ‘smtpmsg='message'’.  Multiline SMTP messages will be concatenated
     into one line.
   • The msmtp error message (only in case of failure and only if
     available): ‘errormsg='message'’
   • The msmtp exit code (from ‘sysexits.h’; ‘EX_OK’ indicates success):
     ‘exitcode=EX_...’

   If a logfile is given with the *note logfile:: command, this log line
will be prepended with the current date and time and appended to the
specified file.

   If syslog logging is enabled with the *note syslog:: command, the log
line is passed to the syslog service with the specified facility.


File: msmtp.info,  Node: Header handling,  Prev: Logging,  Up: Sendmail mode

7.3 Header handling
===================

Msmtp transmits mails unaltered to the SMTP server, with the following
exceptions:
   • The Bcc header(s) will be removed.  This behavior can be changed
     with the *note remove_bcc_headers:: command,
   • A From header will be added if the mail does not have one.  This
     can be changed with the *note add_missing_from_header:: command.
     The header will use the envelope from address and optionally a full
     name set with the ‘-F’ option.
   • A Date header will be added if the mail does not have one.  This
     can be changed with the *note add_missing_date_header:: command.


File: msmtp.info,  Node: Server information mode,  Next: Remote Message Queue Starting mode,  Prev: Sendmail mode,  Up: Top

8 Server information mode
*************************

In server information mode, msmtp prints as much information about the
SMTP server as it can get and then exits.

   The SMTP features that can be detected are:
   • SIZE
     The maximum message size that the SMTP server accepts.
   • PIPELINING
     Whether certain SMTP commands may be send in groups rather than one
     by one.  This can speed up mail transmission if the recipient list
     is long.  This feature is used automatically.
   • STARTTLS
     *Note Transport Layer Security::.
   • AUTH
     *Note Authentication::.
   • DSN
     *Note Delivery Status Notifications::.
   • ETRN
     *Note Remote Message Queue Starting mode::.

   If TLS is activated for server information mode, the following
information will be printed about the SMTP server’s TLS certificate (if
available):
   • Owner information
        • Common Name
        • Organization
        • Organizational unit
        • Locality
        • State or Province
        • Country
   • Issuer information
        • Common Name
        • Organization
        • Organizational unit
        • Locality
        • State or Province
        • Country
   • General
        • Activation time
        • Expiration time
        • SHA256 fingerprint
        • SHA1 fingerprint (deprecated)


File: msmtp.info,  Node: Remote Message Queue Starting mode,  Next: Examples,  Prev: Server information mode,  Up: Top

9 Remote Message Queue Starting mode
************************************

Remote Message Queue Starting (RMQS) is defined in RFC 1985.  It is a
way for a client to request that a server start the processing of its
mail queues for messages that are waiting at the server for the client
machine.  If any messages are at the server for the client, then the
server creates a new SMTP session and sends the messages at that time.

   msmtp can only send the request (using the ETRN SMTP command); a mail
server on the client side should then accept the connection of the
remote SMTP server to receive the mail.

   RMQS requests can be sent with the *note --rmqs:: option.
Destinations defined in RFC 1985 are:
   • HOST
     Request the messages for the given host.
   • @DOMAIN
     Request the messages for the given domain.
   • #QUEUE
     Request the delivery of the messages in the given queue.


File: msmtp.info,  Node: Examples,  Prev: Remote Message Queue Starting mode,  Up: Top

10 Examples
***********

* Menu:

* A user configuration file::
* A system wide configuration file::
* Using msmtp with Mutt::
* Using msmtp with mail::
* Using msmtp with Tor::
* Aliases file::


File: msmtp.info,  Node: A user configuration file,  Next: A system wide configuration file,  Up: Examples

10.1 A user configuration file
==============================

     # Example for a user configuration file ~/.msmtprc
     #
     # This file focusses on TLS and authentication. Features not used here include
     # logging, timeouts, SOCKS proxies, TLS parameters, Delivery Status Notification
     # (DSN) settings, and more.


     # Set default values for all following accounts.
     defaults

     # Use the mail submission port 587 instead of the SMTP port 25.
     port 587

     # Always use TLS.
     tls on

     # Set a list of trusted CAs for TLS. You can use a system-wide default file,
     # as in this example, or download the root certificate of your CA and use that.
     tls_trust_file /etc/ssl/certs/ca-certificates.crt

     # Additionally, you should use the tls_crl_file command to check for revoked
     # certificates, but unfortunately getting revocation lists and keeping them
     # up to date is not straightforward.
     #tls_crl_file ~/.tls-crls


     # A freemail service
     account freemail

     # Host name of the SMTP server
     host smtp.freemail.example

     # As an alternative to tls_trust_file/tls_crl_file, you can use tls_fingerprint
     # to pin a single certificate. You have to update the fingerprint when the
     # server certificate changes, but an attacker cannot trick you into accepting
     # a fraudulent certificate. Get the fingerprint with
     # $ msmtp --serverinfo --tls --tls-certcheck=off --host=smtp.freemail.example
     tls_fingerprint 00:11:22:33:44:55:66:77:88:99:AA:BB:CC:DD:EE:FF:00:11:22:33

     # Envelope-from address
     from joe_smith@freemail.example

     # Authentication. The password is given using one of five methods, see below.
     auth on
     user joe.smith

     # Password method 1: Add the password to the system keyring, and let msmtp get
     # it automatically. To set the keyring password using Gnome's libsecret:
     # $ secret-tool store --label=msmtp \
     #   host smtp.freemail.example \
     #   service smtp \
     #   user joe.smith

     # Password method 2: Store the password in an encrypted file, and tell msmtp
     # which command to use to decrypt it. This is usually used with GnuPG, as in
     # this example. Usually gpg-agent will ask once for the decryption password.
     passwordeval gpg2 --no-tty -q -d ~/.msmtp-password.gpg

     # Password method 3: Store the password directly in this file. Usually it is not
     # a good idea to store passwords in plain text files. If you do it anyway, at
     # least make sure that this file can only be read by yourself.
     #password secret123

     # Password method 4: Store the password in ~/.netrc. This method is probably not
     # relevant anymore.

     # Password method 5: Do not specify a password. Msmtp will then prompt you for
     # it. This means you need to be able to type into a terminal when msmtp runs.


     # A second mail address at the same freemail service
     account freemail2 : freemail
     from joey@freemail.example


     # The SMTP server of your ISP
     account isp
     host mail.isp.example
     from smithjoe@isp.example
     auth on
     user 12345


     # Set a default account
     account default : freemail


File: msmtp.info,  Node: A system wide configuration file,  Next: Using msmtp with Mutt,  Prev: A user configuration file,  Up: Examples

10.2 A system wide configuration file
=====================================

     # A system wide configuration is optional.
     # If it exists, it usually defines a default account.
     # This allows msmtp to be used like /usr/sbin/sendmail.
     account default

     # The SMTP smarthost.
     host mailhub.oursite.example

     # Construct envelope-from addresses of the form "user@oursite.example".
     #auto_from on
     #maildomain oursite.example

     # Use TLS.
     #tls on
     #tls_trust_file /etc/ssl/certs/ca-certificates.crt

     # Syslog logging with facility LOG_MAIL instead of the default LOG_USER.
     syslog LOG_MAIL


File: msmtp.info,  Node: Using msmtp with Mutt,  Next: Using msmtp with mail,  Prev: A system wide configuration file,  Up: Examples

10.3 Using msmtp with Mutt
==========================

Create a configuration file for msmtp and add the following lines to
your Mutt configuration file:
     set sendmail="/path/to/msmtp"
     set use_from=yes
     set realname="Your Name"
     set from=you@example.com
     set envelope_from=yes

   The ‘envelope_from=yes’ option lets Mutt use the ‘-f’ option of
msmtp.	 Therefore msmtp chooses the first account that matches the from
address you@example.com.  Alternatively, you can use the ‘-a’ option:
     set sendmail="/path/to/msmtp -a my_account"

   Or set everything from the command line:
     set sendmail="/path/to/msmtp --host=mailhub -f me@example.com --tls"
   *Note Choosing an account::.

   If you have multiple mail accounts in your msmtp configuration file
and let Mutt use the ‘-f’ option to choose one, you can easily switch
accounts in Mutt with the following Mutt configuration lines:
     macro generic "<esc>1" ":set from=you@example.com"
     macro generic "<esc>2" ":set from=you@your-employer.example"
     macro generic "<esc>3" ":set from=you@some-other-provider.example"
   Now you can use <esc>1, <esc>2, and <esc>3 to switch accounts.

   The following example uses a different approach: it maps the single
key ‘<tab>’ in Compose context for switching between the various account
in a handy visual way.  In the same Compose context, ‘=’ is mapped in
order to show the current msmtp account.  This example was contributed
by Thomas Baruchel.
     # Define <tab> and = in order to switch or see the current msmtp account
     # Don't forget to put the right path for msmtp binary
     macro compose \Cx_ ":set sendmail"
     macro compose \Cx| "\Cx_ = \"/usr/local/bin/msmtp"
     macro compose \Cx& ":macro compose \\t \\Cx"
     macro compose <tab> "\Cx0"
     macro compose = "\Cx_\n"
     # Put the account in the following lines (here three accounts)
     # Don't forget to put the number of the account at the beginning
     # of the line, and the number of the next account after the '&'
     macro compose \Cx0 "\Cx|\"\n\Cx&1\n\Cx_\n" # default and switch to 1
     macro compose \Cx1 "\Cx| -a example_account\"\n\Cx&2\n\Cx_\n" # switch to 2
     macro compose \Cx2 "\Cx| -a gmail\"\n\Cx&0\n\Cx_\n" # switch to 0
     # End of the accounts


File: msmtp.info,  Node: Using msmtp with mail,  Next: Using msmtp with Tor,  Prev: Using msmtp with Mutt,  Up: Examples

10.4 Using msmtp with mail
==========================

Define a default account, and put the following into ‘~/.mailrc’:
     set sendmail="/path/to/msmtp"

   You need to define a default account, because mail does not allow
extra options to the msmtp command line.


File: msmtp.info,  Node: Using msmtp with Tor,  Next: Aliases file,  Prev: Using msmtp with mail,  Up: Examples

10.5 Using msmtp with Tor
=========================

Use the following settings:
     proxy_host 127.0.0.1
     proxy_port 9050
     tls on
   Use an IP address as proxy host name, so that msmtp does not leak a
DNS query when resolving it.
TLS is required to prevent exit hosts from reading your SMTP session.
You also need *note tls_trust_file:: or *note tls_fingerprint:: to check
the server identity.  Do not set ‘domain’ to something that you do not
want to reveal (do not set it at all if possible).


File: msmtp.info,  Node: Aliases file,  Prev: Using msmtp with Tor,  Up: Examples

10.6 Aliases file
=================

     # Example aliases file

     # Send root to Joe and Jane
     root: joe_smith@example.com, jane_chang@example.com

     # Send cron to Mark
     cron: mark_jones@example.com

     # Send everything else to admin
     default: admin@domain.example



Tag Table:
Node: Top640
Node: Introduction1681
Node: Configuration files3539
Ref: defaults4910
Ref: account5074
Ref: host5449
Ref: port5629
Ref: timeout5805
Ref: proxy_host6011
Ref: proxy_port6482
Ref: protocol6648
Ref: domain6819
Ref: auth7350
Ref: user7703
Ref: password7881
Ref: passwordeval8178
Ref: ntlmdomain8461
Ref: tls8647
Ref: tls_starttls8875
Ref: tls_trust_file9041
Ref: tls_crl_file9462
Ref: tls_fingerprint9621
Ref: tls_key_file10101
Ref: tls_cert_file10346
Ref: tls_certcheck10567
Ref: tls_min_dh_prime_bits10766
Ref: tls_priorities11137
Ref: from11558
Ref: auto_from11738
Ref: maildomain12248
Ref: dsn_notify12373
Ref: dsn_return13101
Ref: add_missing_from_header13635
Ref: add_missing_date_header13821
Ref: remove_bcc_headers14007
Ref: logfile14164
Ref: syslog14364
Ref: aliases14641
Node: Invocation15539
Ref: --serverinfo16869
Ref: --rmqs17151
Ref: --auth18738
Ref: --user18859
Ref: --passwordeval18950
Ref: --tls-starttls19112
Ref: --tls-trust-file19207
Ref: --tls-crl-file19301
Ref: --tls-fingerprint19424
Ref: --tls-key-file19557
Ref: --tls-cert-file19645
Ref: --tls-certcheck19736
Ref: --tls-min-dh-prime-bits19855
Ref: --tls-priorities19997
Ref: --from20175
Ref: --auto-from20549
Ref: --maildomain20661
Ref: --dsn-notify20775
Ref: --dsn-return20903
Ref: --add-missing-from-header21130
Ref: --add-missing-date-header21274
Ref: --remove-bcc-headers21418
Ref: --logfile21541
Ref: --syslog21630
Ref: Choosing an account22887
Ref: Files23750
Ref: Environment24192
Node: Transport Layer Security25244
Node: Authentication29172
Node: Delivery Status Notifications33122
Node: Sendmail mode34317
Node: Envelope-from address34641
Node: Logging35176
Node: Header handling36711
Node: Server information mode37435
Node: Remote Message Queue Starting mode38927
Node: Examples39954
Node: A user configuration file40240
Node: A system wide configuration file43576
Node: Using msmtp with Mutt44361
Node: Using msmtp with mail46805
Node: Using msmtp with Tor47201
Node: Aliases file47826

End Tag Table


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