My Configuration: I use an IIS5 SMTP server to forward email to my Exchange 5.5 server. There is no Spam filtration on the IIS5 box (yet) The problem: I have several executives in my company that receive mews flashes from various list servers. The L-SOFT list server in particular. I have spoken with them and they theorize that it is because they send a "return-path: <>" in the message header. Here is the header of the list server email I receive: =============================================== Received: from gbstmail002.globest.com ([220.127.116.11]) by mailguard.conway.com with Microsoft SMTPSVC(5.0.2195.5329); Mon, 20 Jan 2003 15:57:46 -0500 Received: from gbstmail002 (gbstmail002.globest.com) by gbstmail002.globest.com (LSMTP for Windows NT v1.1b) with SMTP id <0.0036BD7A@xxxxxxxxxxxxxxxxxxxxxxx>; Mon, 20 Jan 2003 15:56:32 -0500 Date: Mon, 20 Jan 2003 15:56:32 -0500 From: "L-Soft list server at GlobeSt.com (1.8d)" <LISTSERV@xxxxxxxxxxxxxxxxxxxxxxx> Subject: Output of your job "lenny.burns" To: lenny.burns@xxxxxxxxxx Return-Path: <> Message-ID: <MAILGUARDFCHOzyfyz50000163c@xxxxxxxxxxxxxxxxxxxx> X-OriginalArrivalTime: 20 Jan 2003 20:57:46.0081 (UTC) FILETIME=[954E9D10:01C2C0C6] =============================================== Here are the contents of the .BDR file associated with it: =============================================== Unable to deliver this message because the follow error was encountered: "This message is a delivery status notification that cannot be delivered.". The specific error code was 0xC00402C7. The message sender was <>. The message was intended for the following recipients. xxxx.xxxxx@xxxxxxxxxx =============================================== Anyone here ever see this? And what is a .BDP file?