msmtp is an SMTP client.

In the default mode, it transmits a mail to an SMTP server (for example at a 
free mail provider) which does the delivery. 
To use this program with your mail user agent (MUA), create a configuration 
file with your mail account(s) and tell your MUA to call msmtp instead of 
/usr/sbin/sendmail.

Features include:
- SMTP AUTH methods PLAIN, LOGIN, CRAM-MD5 and EXTERNAL
  (and GSSAPI, DIGEST-MD5 and NTLM when compiled with GNU SASL support)
- TLS encrypted connections with the GnuTLS or OpenSSL libraries
  (including server certificate verification and the possibility to send
  a client certificate)
- LMTP support
- DSN (Delivery Status Notification) support
- RMQS (Remote Message Queue Starting) support (ETRN keyword)
- PIPELINING support for increased transmission speed
- IPv6 support
- support for multiple accounts
- sendmail compatible interface (command line options and exit codes)

msmtp runs on UNIX-like systems, Windows, and DOS.
In particular, supported platforms include:
GNU/Linux (glibc, uclibc or dietlibc), FreeBSD, NetBSD, OpenBSD, Solaris, AIX,
HP-UX, MacOS X, OpenDarwin, Cygwin on Win32, Windows 9x/ME/NT/2000/XP/2003, 
MS-DOS/FreeDOS+DJGPP+Watt32.

Optional libraries:
If you want TLS/SSL support, you need either OpenSSL >=0.9.6 or GnuTLS >=1.2.0.
If you want GNU SASL support, you need GNU SASL >=0.2.4.

The homepage of this program is http://msmtp.sourceforge.net/

This program is free software; you can redistribute it and/or modify it under 
the terms of the GNU General Public License (see the file COPYING) as published
by the Free Software Foundation; either version 2 of the License, or (at your 
option) any later version.

msmtp is released under the GPL with the additional exemption that
compiling, linking, and/or using OpenSSL is allowed.
