Authenticated Email - 1. header question 2. sending to a list question

I’m using the script at the bottom of this to send authenticated email from a particular site.
I will be using this to send to a list of approx 2100 subscribers.

Two Questions.

Testing with a single address, the email passes authentication and is sent as expected. However, looking at the headers of the test email I receive, I’m seeing:
“X-Comment: Sending client does not conform to RFC822 minimum requirements”
What is this, and is there a way to fix it or is it not a concern?

To send to my list ( …and I’ve cleared with my host that I can send this many with certain constraints), I should simply loop my recordset thusly? (I usually do this in Coldfusion, and it works a little differently there…)

   while($row = $rs->fetch_assoc()){
     $SMTPMail = new SMTPClient ($SmtpServer, $SmtpPort, $SmtpUser, $SmtpPass, $from, $row['subscribed_address'], $subject, $body);
     $SMTPChat = $SMTPMail->SendMail();

That looks like it’s opening/closing the connection for every single one of my 2100 emails. That sounds like a bad idea. Yes? No?
What’s “best practice” for this? Hopefully this isn’t too much of a noob question…

  $SmtpPort="25"; //default

class SMTPClient

function SMTPClient ($SmtpServer, $SmtpPort, $SmtpUser, $SmtpPass, $from, $to, $subject, $body)

$this->SmtpServer = $SmtpServer;
$this->SmtpUser = base64_encode ($SmtpUser);
$this->SmtpPass = base64_encode ($SmtpPass);
$this->from = $from;
$this->to = $to;
$this->subject = $subject;
$this->body = $body;

if ($SmtpPort == "") {
   $this->PortSMTP = 25;
} else {
   $this->PortSMTP = $SmtpPort;

function SendMail ()
if ($SMTPIN = fsockopen ($this->SmtpServer, $this->PortSMTP))
  fputs ($SMTPIN, "EHLO ".$HTTP_HOST."\\r\
  $talk["hello"] = fgets ( $SMTPIN, 1024 );
  fputs($SMTPIN, "auth login\\r\
  fputs($SMTPIN, $this->SmtpUser."\\r\
  fputs($SMTPIN, $this->SmtpPass."\\r\
  fputs ($SMTPIN, "MAIL FROM: <".$this->from.">\\r\
  $talk["From"] = fgets ( $SMTPIN, 1024 );
  fputs ($SMTPIN, "RCPT TO: <".$this->to.">\\r\
  $talk["To"] = fgets ($SMTPIN, 1024);
  fputs($SMTPIN, "DATA\\r\
  $talk["data"]=fgets( $SMTPIN,1024 );
  fputs($SMTPIN, "To: <".$this->to.">\\r\
From: <".$this->from.">\\r\
  fputs ($SMTPIN, "QUIT\\r\
  return $talk;

  $to = $_POST['to'];
  $from = $_POST['from'];
  $subject = $_POST['sub'];
  $body = $_POST['message'];
  $SMTPMail = new SMTPClient ($SmtpServer, $SmtpPort, $SmtpUser, $SmtpPass, $from, $to, $subject, $body);
  $SMTPChat = $SMTPMail->SendMail();

I finally gave up on the above and went with PEAR to send the email. However, was STILL getting:

Solution to this part was to add a DATE object to the headers,

$headers['Date']=date("D , d M Y H:i:s O");