Good day Bros. I needed a simple mail reflector and did not need all the functionality of listerv or majordomo, et al. So I wrote a script for this purpose myself. It is working fine as far as anticipated functions. Here is the code:

#!/usr/bin/perl -w
use strict;
use Mail::POP3Client;
use Mail::Mailer;

our $junk;

my $pophost = '';
my $popuser = '';
my $poppw = '';
my $reflectoraddr = '';
my $subjprefix = '';
my $errorfrom = '';
my $errorbcc = '';

my %participants;
open(IN,"participants.txt") or die "Can't open participants.txt: $!\n"
+;
while(<IN>) {
    chop;
    if ($_) {
        $participants{$_} = 1;
    }
}
close IN;

my $pop = Mail::POP3Client->new(HOST => $pophost, USER => $popuser, PA
+SSWORD => $poppw);
our $mailer = new Mail::Mailer;
my $msgcount = $pop->Count();
print "$msgcount messages\n";
foreach my $k (1..1) {
    my %header;
    my $head = $pop->Head($k);
    my @lines = split(/\n/,$head);
    my $headerinfo;
    my ($key,$value);
    for my $i (0..$#lines) {
        $lines[$i] =~ s/\r/ /g;
        if (substr($lines[$i],0,1) =~ /[A-Z]/) {
            if ($lines[$i] =~ /^Date/) {
                $key = "Date";
                ($value = $lines[$i]) =~ s/Date: //;
            }
            else {
                ($key,$value) = split(/\:/,$lines[$i]);
            }
            $header{$key} = $value;
        }
        else {
            $lines[$i] =~ s/^\s+//g;
            $header{$key} .= " $lines[$i]";
        }
    }
    if ($header{'Subject'} !~ /undeliverable|delivery (failure|error)/
+i) {
        delete($header{'Received'});
        delete($header{'Envelope-to'});           
        $header{'Reply-to'} = $reflectoraddr;
        delete($header{'To'});
        $header{'Subject'} =~ s/\[Crawdad\] //g;
        my $body = $pop->Body($k);
        open (OUT,">bodytext.txt") or die "No output: $!\n";
        print OUT $body;
        close OUT;
        my $from;
        if ($header{'From'} =~ /\<.+\>/) {
            ($junk, $from) = split(/[\<\>]/,$header{'From'});
        }
        else {
            $from = $header{'From'};
        }
        if (defined($participants{$from})) {
            $header{'Subject'} = "\[$subjprefix\] ".$header{'Subject'}
+;
            foreach my $p (keys %participants) {
                unless ($header{'From'} =~ /$p/) {
                    print "Sending to $p\n";
                    $header{'To'} = $p;
                    $mailer->open(\%header);
                    print $mailer $body;
                    $mailer->close;
                }
            }
        }
        else {
            print "Error to $from\n";
            errormsg(\%header,$from);
        }
    }
    $pop->Delete($k);
}
$pop->Close();

sub errormsg {
    my ($header,$from) = @_;
    my $errormsg = "The address $from is not authorized to send to thi
+s discussion list.\n\nIf you are a registered user, it may be that yo
+u are sending from an e-mail account other than the one you normally 
+use.  Please contact the discussion host to have this account added."
+;
    delete($$header{'Content-Type'});
    $$header{'Subject'} = 'ERROR: '.$$header{'Subject'};
    $$header{'From'} = $errorfrom;
    $$header{'To'} = $from;
    $mailer->open($header);
    print $mailer $errormsg;
    $mailer->close;
    return;
}
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Since this is a reflector that will run on a chron job or something like that, I am concerned about the possibility of this thing getting error e-mails (e.g. if an address fails, an account gets suspended, etc.) and getting in a mail loop situation via sub errormsg. I have tried to prevent this with if ($header{'Subject'} !~ /undeliverable|delivery (failure|error)/i) but I'm not sure if this is sufficient or the best way to do it.

Any Mail Monks out there who can comment on whether this is good enough? Is there some kind of header I could look at to detect failures, rather than depending on the subject? I've looked around in the SMTP docs and I haven't seen anything that looks suitable.

Thanks.......Steve