=encoding utf8

=head1 NAME

Mail::Transport::Sendmail - transmit messages using external Sendmail program

=head1 INHERITANCE

 Mail::Transport::Sendmail
   is a Mail::Transport::Send
   is a Mail::Transport
   is a Mail::Reporter

=head1 SYNOPSIS

  my $sender = Mail::Transport::Sendmail->new(...);
  $sender->send($message);

=head1 DESCRIPTION

Implements mail transport using the external C<'Sendmail'> program.
When instantiated, the mailer will look for the binary in specific system
directories, and the first version found is taken.

Some people use Postfix as MTA.  Postfix can be installed as replacement
for Sendmail: is provides a program with the same name and options.  So,
this module supports postfix as well.

B<WARNING:> When you do bulk email sending with local delivery via
Postfix, you can probably better use the SMTP backend to connect
to postfix.  The C<sendmail> command delivers to C<maildrop>.  From
C<maildrop>, the C<pickupd> will only sequentially insert messages
into C<cleanup>.  That process can take considerable elapse time.
Directly inserting via C<smtpd> will parallellize the cleanup process.

Extends L<"DESCRIPTION" in Mail::Transport::Send|Mail::Transport::Send/"DESCRIPTION">.

=head1 METHODS

Extends L<"METHODS" in Mail::Transport::Send|Mail::Transport::Send/"METHODS">.

=head2 Constructors

Extends L<"Constructors" in Mail::Transport::Send|Mail::Transport::Send/"Constructors">.

=over 4

=item $class-E<gt>B<new>(%options)

Inherited, see L<Mail::Reporter/"Constructors">

 -Option          --Defined in     --Default
  executable        Mail::Transport  undef
  hostname          Mail::Transport  'localhost'
  interval          Mail::Transport  30
  password          Mail::Transport  undef
  port              Mail::Transport  undef
  proxy             Mail::Transport  undef
  retry             Mail::Transport  <unlimited>
  sendmail_options                   []
  timeout           Mail::Transport  120
  username          Mail::Transport  undef
  via               Mail::Transport  'sendmail'

=over 2

=item executable => $file

=item hostname => $host|\@hosts

=item interval => $span

=item password => $password

=item port => $port

=item proxy => $path

=item retry => $count|undef

=item sendmail_options => ARRAY

Add to the command-line of the started sendmail MTU a list of
separate words.  So say C< [ '-f', $file ] > and not C< [ "-f $file" ] >,
because the latter will be taken by sendmail as one word only.

=item timeout => $span

=item username => $username

=item via => CLASS|$name

=back

=back

=head2 Attributes

Extends L<"Attributes" in Mail::Transport::Send|Mail::Transport::Send/"Attributes">.

=head2 Sending mail

Extends L<"Sending mail" in Mail::Transport::Send|Mail::Transport::Send/"Sending mail">.

=over 4

=item $obj-E<gt>B<destinations>( $message, [$address|\@addresses] )

Inherited, see L<Mail::Transport::Send/"Sending mail">

=item $obj-E<gt>B<putContent>($message, $fh, %options)

Inherited, see L<Mail::Transport::Send/"Sending mail">

=item $obj-E<gt>B<send>($message, %options)

Inherited, see L<Mail::Transport::Send/"Sending mail">

=item $obj-E<gt>B<trySend>($message, %options)

Inherited, see L<Mail::Transport::Send/"Sending mail">

 -Option          --Default
  sendmail_options  undef

=over 2

=item sendmail_options => ARRAY

=back

=back

=head2 Server connection

Extends L<"Server connection" in Mail::Transport::Send|Mail::Transport::Send/"Server connection">.

=over 4

=item $obj-E<gt>B<findBinary>( $name, [@directories] )

Inherited, see L<Mail::Transport/"Server connection">

=item $obj-E<gt>B<remoteHost>()

Inherited, see L<Mail::Transport/"Server connection">

=item $obj-E<gt>B<retry>()

Inherited, see L<Mail::Transport/"Server connection">

=back

=head2 Error handling

Extends L<"Error handling" in Mail::Transport::Send|Mail::Transport::Send/"Error handling">.

=over 4

=item $obj-E<gt>B<AUTOLOAD>()

Inherited, see L<Mail::Reporter/"Error handling">

=item $obj-E<gt>B<notImplemented>()

Inherited, see L<Mail::Reporter/"Error handling">

=back

=head2 Cleanup

Extends L<"Cleanup" in Mail::Transport::Send|Mail::Transport::Send/"Cleanup">.

=over 4

=item $obj-E<gt>B<DESTROY>()

Inherited, see L<Mail::Reporter/"Cleanup">

=back

=head1 DIAGNOSTICS

=over 4

=item Error: Errors when closing sendmail mailer $program: $!

The was no problem starting the sendmail mail transfer agent, but for
some specific reason the message could not be handled correctly.
Cast by C<trySend()>

=item Fault: cannot open pipe to $program: $!

Cast by C<trySend()>

=item Error: class $package does not implement method $method.

Fatal error: the specific C<$package> (or one of its superclasses) does not
implement this method where it should. This message means that some other
related classes do implement this method however the class at hand does
not.  Probably you should investigate this and probably inform the author
of the package.
Cast by C<notImplemented()>

=item Warning: message has no destination.

It was not possible to figure-out where the message is intended to go to.
Cast by C<destinations()>

=item Warning: resent group does not specify a destination.

The message which is sent is the result of a bounce (for instance
created with L<Mail::Message::bounce()|Mail::Message::Construct::Bounce/"Constructing a message">), and therefore starts with a
C<Received> header field.  With the C<bounce>, the new destination(s)
of the message are given, which should be included as C<Resent-To>,
C<Resent-Cc>, and C<Resent-Bcc>.

The C<To>, C<Cc>, and C<Bcc> header information is only used if no
C<Received> was found.  That seems to be the best explanation of the RFC.

As alternative, you may also specify the C<to> option to some of the senders
(for instance L<Mail::Transport::SMTP::send(to)|Mail::Transport::Send/"Sending mail"> to overrule any information
found in the message itself about the destination.
Cast by C<destinations()>

=back

=head1 SEE ALSO

This module is part of Mail-Transport version 4.01,
built on December 13, 2025. Website: F<http://perl.overmeer.net/CPAN/>

=head1 LICENSE

For contributors see file ChangeLog.

This software is copyright (c) 2001-2025 by Mark Overmeer.

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.

