SMTP: Missing Attachment Name in Client when Using PMDF Mailer

SYMPTOMS

Upon opening an attachment of a message from SMTP, the attachment name may not be found if the TCP/IP mail routing host used a PMDF mailer. The attachment itself is not lost, and is viewable.

CAUSE

The problem is in the RFC 822 header fields, and the order in which they appear. When using the PMDF mailer on the TCP/IP mail routing host, the "X-MS-Attachment" header line is re-ordered to appear before the "Encoding" header line. The SMTP gateway uses the "Encoding" header to build up a link list to describe the attachments and then fills in the file attributes later when it parses the "X-MS-Attachment" lines. If these two lines appear in the wrong order, the link list does not exist when the "X-MS-Attachment" header lines are being parsed. The gateway then ignores these lines, losing the names of any attachments.

Looking at a log file generated by starting the SMTP gateway with the "-cd" and "-lacsy" switches, the incorrect header fields appear as:

13:22:41 - Sending message to Microsoft Mail 13:22:42 - Header: Return-Path: <root@company.com> 13:22:42 - Header: Received: from company.com by smtp-gateway.company.com 13:22:42 - Header: id <2C431991@smtp-gateway.company.com>; Tue, 13 Jul 93 13:22:41 PDT 13:22:42 - Header: Date: Tue, 13 Jul 1993 13:22:00 -0700 (PDT) 13:22:42 - Header: From: Root <root@company.com> 13:22:42 - Header: Subject: Testing word attachment thru SMTPgate 13:22:42 - Header: To: "ROOT (COMPANY)" <root@company.oom> 13:22:42 - Header: X-Mailer: Microsoft Mail V3.0 13:22:42 - Header: X-MS-Attachment: smtptest.doc 1024 07-13-1993 13:20 13:22:42 - Header: Encoding: 2 TEXT, 29 UUENCODE 13:22:42 - Header:

A correct set of headers should look like this:

13:22:41 - Sending message to Microsoft Mail 13:22:42 - Header: Return-Path: <root@company.com> 13:22:42 - Header: Received: from company.com by smtp-gateway.company.com 13:22:42 - Header: id <2C431991@smtp-gateway.company.com>; Tue, 13 Jul 93 13:22:41 PDT 13:22:42 - Header: Date: Tue, 13 Jul 1993 13:22:00 -0700 (PDT) 13:22:42 - Header: From: Root <root@company.com> 13:22:42 - Header: Subject: Testing word attachment thru SMTPgate 13:22:42 - Header: To: "ROOT (COMPANY)" <root@company.oom> 13:22:42 - Header: X-Mailer: Microsoft Mail V3.0 13:22:42 - Header: Encoding: 2 TEXT, 29 UUENCODE 13:22:42 - Header: X-MS-Attachment: smtptest.doc 1024 07-13-1993 13:20 13:22:42 - Header:

RESOLUTION

Obtain the latest version of PMDF, from Innosoft. The latest version no longer re-orders the headers.