Here's the script that's builds/sends the email:
$boundary = md5(date('U'));
$to = $email;
$subject = "My Subject";
$headers = "From: [email protected]" . "\r\n".
"X-Mailer: PHP/".phpversion() ."\r\n".
"MIME-Version: 1.0" . "\r\n".
"Content-Type: multipart/alternative; boundary=--$boundary". "\r\n".
"Content-Transfer-Encoding: 7bit". "\r\n";
$text = "You really ought remember the birthdays";
$html = '<html>
<head>
<title>Birthday Reminders for August</title>
</head>
<body>
<p>Here are the birthdays upcoming in August!</p>
<table>
<tr>
<th>Person</th><th>Day</th><th>Month</th><th>Year</th>
</tr>
<tr>
<td>Joe</td><td>3rd</td><td>August</td><td>1970</td>
</tr>
<tr>
<td>Sally</td><td>17th</td><td>August</td><td>1973</td>
</tr>
</table>
</body>
</html>
';
$message = "Multipart Message coming up" . "\r\n\r\n".
"--".$boundary.
"Content-Type: text/plain; charset=\"iso-8859-1\"" .
"Content-Transfer-Encoding: 7bit".
$text.
"--".$boundary.
"Content-Type: text/html; charset=\"iso-8859-1\"".
"Content-Transfer-Encoding: 7bit".
$html.
"--".$boundary."--";
mail("[email protected]", $subject, $message, $headers);
It sends the message just fine, and my recipient receives it, but they get the whole thing in text/plain instead of in multipart/alternative. Viewing the source of the received message gives this (lots of cruft removed):
Delivered-To: [email protected]
Received: by 10.90.100.4 with SMTP id x4cs111413agb;
Wed, 25 Mar 2009 16:39:32 -0700 (PDT)
Received: by 10.100.153.6 with SMTP id a6mr85081ane.123.1238024372342;
Wed, 25 Mar 2009 16:39:32 -0700 (PDT)
Return-Path: <[email protected]>
--- snip ---
Date: Wed, 25 Mar 2009 17:37:36 -0600 (MDT)
Message-Id: <[email protected]>
To: [email protected]
Subject: My Subject
From: [email protected]
X-Mailer: PHP/4.3.9
MIME-Version: 1.0
Content-Type: text/plain;
boundary="--66131caf569f63b24f43d529d8973560"
Content-Transfer-Encoding: 7bit
X-OriginalArrivalTime: 25 Mar 2009 23:38:30.0531 (UTC) FILETIME=[CDC4E530:01C9ADA2]
X-TM-AS-Product-Ver: SMEX-8.0.0.1181-5.600.1016-16540.005
X-TM-AS-Result: No--4.921300-8.000000-31
X-TM-AS-User-Approved-Sender: No
X-TM-AS-User-Blocked-Sender: No
Multipart Message coming up
--66131caf569f63b24f43d529d8973560
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
You really ought remember the birthdays
--66131caf569f63b24f43d529d8973560
Content-Type: text/html; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
<html>
<head>
<title>Birthday Reminders for August</title>
</head>
<body>
<p>Here are the birthdays upcoming in August!</p>
<table>
<tr>
<th>Person</th><th>Day</th><th>Month</th><th>Year</th>
</tr>
<tr>
<td>Joe</td><td>3rd</td><td>August</td><td>1970</td>
</tr>
<tr>
<td>Sally</td><td>17th</td><td>August</td><td>1973</td>
</tr>
</table>
</body>
</html>
--66131caf569f63b24f43d529d8973560--
It looks like the content-type header is getting changed along the way from multipart/alternative to text/plain. I'm no sysadmin, so if this is a sendmail issue I'm in way over my head. Any suggestions?