Sending SMTP auth information via PHP?

I'm working on a mail script that talks direct to SMTP instead of using mail(), but my SMTP server requires authentication. How can I pass AUTH information to the server via PHP? Here's the code I have now: function open($smtpserver,$ti=2){ $this->fp = fsockopen($smtpserver, 25, $errno, $errstr, $ti); if (!$this->fp){ echo "<b>Error opening $smtpserver</b><br><font color=\"red\">$errstr ($errno).</font><hr>\n"; exit; } $this->recv(); } Should I pass it somewhere in the fsockopen? Later on I have this code to send the mail: $mySTMPprocess->send("HELO mail.server.com"); $mySTMPprocess->send("MAIL FROM:$from"); $mySTMPprocess->send("RCPT TO:$email"); $mySTMPprocess->send("DATA"); $mySTMPprocess->send($theEmailText); $mySTMPprocess->send("RSET"); $mySTMPprocess->send("QUIT"); Do I need to pass it at the time of sending? The mail works great until I try to send to addresses outside of the domain. Thanks in advance! __________________________________________________ Do you Yahoo!? Yahoo! Tax Center - File online, calculators, forms, and more http://tax.yahoo.com