May I recommend Net::SMTP. Here's a piece of code that has been reliable since this time last year. Its very easy to understand.

sub vianetsmtp
{
my $from     = $_[0];
my $to        = $_[1];
my $subject     = $_[2];
my $body     = $_[3];

$smtp = Net::SMTP->new    ($maileroutrelay,
            Timeout => $mailerouttimeout,
               Debug   => $maileroutdebug
                  ) or logtofile ($logdir.'/usermailer',"can't create 
+new smtp mail object");
defined ($smtp) or die;
my $domainmessg = $smtp->domain;
my $bannermessg = $smtp->banner;
$smtp->mail($from);
$smtp->to($to);
$smtp->data;
$smtp->datasend("from:$from");
$smtp->datasend("\n");
$smtp->datasend("subject:$subject");
$smtp->datasend("\n");
$smtp->datasend("$body");
$smtp->datasend("\n");
$smtp->quit;
undef $smtp;
logtofile ($logdir.'/usermailer',"usermailer: mail written via net::sm
+tp");
return 1;
}
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The extra defined getout is probably redundant, but I know better than to mess with working code :) Most mail problems are to do with routing ime, half the time its getting out but not being routed. If you use a direct method like above you can send to the destination mailserver in one.