Hello, that's what I get from PayPal by processing my script: I add the send it back to PayPal via LWP and get back 'INVALID' And ... I think 'tx' should be 'txn_id' 'st' should be 'payment_status' and so on I'm helpless ... what's going wrong ?

sub ack_ipn {
# ack the ipn
my $ua = new LWP::UserAgent;

# build the request
my $req = new HTTP::Request("POST", $PAYPAL_URL);
$req->content_type("application/x-www-form-urlencoded");
$req->content(query_string() . "&cmd=_notify-validate");
# get the response
my $resp = $ua->request($req);
if (($resp->is_success) && ($resp->content eq "VERIFIED")) {
return 1;
} else {
# attempt to identify error
if (($resp->is_success) && ($resp->content eq "INVALID")) {
error_notify("Notification received was NOT from PayPal - Message was ignored.",
"acknowledge IPN", 0, 0);
}
else {
error_notify("Notification could not be acknowledged due to a network or PayPal issue. "
."PayPal will retry until it succeeds.", "acknowledge IPN", 1, 0);
}
return undef;
}
}

Andrew W. Chang
President
Scorpion Systems
Winner PayPal® Star Developer Award 2005
AndrewC@scorpionsystems.net
http://www.scorpionsystems.net

Phone: 631.789.5785
Fax : 631.842.4321

print "Content-Type: text/html\n\n";
# read post from PayPal system and add 'cmd'
read (STDIN, $query, $ENV{'CONTENT_LENGTH'});
$query .= '&cmd=_notify-validate';

# post back to PayPal system to validate
use LWP::UserAgent;
$ua = new LWP::UserAgent;
$req = new HTTP::Request 'POST','http://www.paypal.com/cgi-bin/webscr';
$req->content_type('application/x-www-form-urlencoded');
$req->content($query);
$res = $ua->request($req);

# split posted variables into pairs
@pairs = split(/&/, $query);
$count = 0;
foreach $pair (@pairs) {
($name, $value) = split(/=/, $pair);
$value =~ tr/+/ /;
$value =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C", hex($1))/eg;
$variable{$name} = $value;
$count++;
}

# assign posted variables to local variables
$receiver_email = $variable{'receiver_email'};

$txn_id = $variable{'txn_id'};
$txn_type = $variable{'txn_type'};
$item_name = $variable{'item_name'};
$item_number = $variable{'item_number'};
$invoice = $variable{'invoice'};

$payment_status = $variable{'payment_status'};
$pending_reason = $variable{'pending_reason'};
$payment_gross = $variable{'mc_gross'};
$payment_currency = $variable{'mc_currency'};
$payment_date = $variable{'payment_date'};
$payment_type = $variable{'payment_type'};

$payer_id = $variable{'payer_id'};
$payer_email = $variable{'payer_email'};
$payer_status = $variable{'payer_status'};
$first_name = $variable{'first_name'};
$last_name = $variable{'last_name'};
$address_street = $variable{'address_street'};
$address_city = $variable{'address_city'};
$address_state = $variable{'address_state'};
$address_zip = $variable{'address_zip'};
$address_country = $variable{'address_country'};
$address_status = $variable{'address_status'};

Andrew W. Chang
President
Scorpion Systems
Winner PayPal® Star Developer Award 2005
AndrewC@scorpionsystems.net
http://www.scorpionsystems.net

Phone: 631.789.5785
Fax : 631.842.4321

The return/PDT url will receive these variables:

tx : transaction id
st : status of the payment
amt : amount
cc : currency code
cm : custom value
sig : encrypted signature

Your script must POST back the txn token, along with the identity token, with cmd=_notify-synch.

PayPal will POST back SUCCESS/FAIL and the data.

https://www.paypal.com/pdt

Turn on IPN if you want all that post info 'no hablo englis' jerkwad was refering to.