use strict;
use warnings;
use Net::SMTP;

$host = "mail.host.com";
$port = 25;

$smtp = Net::SMTP->new($host, port=>$port);
$smtp->mail("test\@domain.com");
$smtp->recipient("test\@domain2.com");
$smtp->data;
$smtp->datasend("From: test\@domain.com");
$smtp->datasend("To: test\@domain2.com");  
$smtp->datasend("Subject: Test");
$smtp->datasend("\n");
$smtp->datasend ("This is a test");

$smtp->dataend;
$smtp->quit;