How to configure smtp to send emails in php under linux

include_once("class.phpmailer.php");
/**
 * Define email module configuration information
*/
define("SMTP_HOST","smtp.mail.yahoo.com "); // SMTP host
define("SMTP_MAIL"," XXXX@yahoo.cn"); // SMTP user email
define("SMTP_PASS"," XXXX"); // Password for SMTP
define("SERVICE_MAIL"," XXXX@yahoo.cn"); // SMTP user email
define("SERVICE_NAME","PHPBOOK Email Test"); // SMTP name used
/**
 * Use phpmailer to send email module
 *
 * @param string $email
 * @param string $user
 * @param string $subject
 * @param string $body
 * @return bool
*/
function sendMail($email,$user,$subject,$body)
{
 $mail = new PHPMailer();
 //$this;
 $mail ->IsSMTP(); // Set up SMTP
 $mail->Host = SMTP_HOST; // Set SMTP server address
 $mail->SMTPAuth = true; // Turn on SMTP permission verification
 $mail-> Username = SMTP_MAIL; // SMTP username
 $mail->Password = SMTP_PASS; // SMTP server password
 $mail->From = SERVICE_MAIL; // Set sender address
 $mail->FromName = SERVICE_NAME; // Set the sender's name
 $mail->AddAddress($email, $user); // Add the recipient's address
 $mail->AddReplyTo(SERVICE_MAIL, SERVICE_NAME); / / Set reply address
 $mail->WordWrap = 50; // Set display format
 $mail->IsHTML(true); // Set email to support html
 $mail-> ;Subject = $subject;
 $mail->Body = $body;
 $mail->AltBody = ""; // Text type mail
 if(!$mail- >Send())
 {
 return $mail->ErrorInfo;
 }
 return true;
}
//Start sending test email: fsockopen() [function.fsockopen ]: php_network_getaddresses: getaddrinfo failed: Name or service not known in /var/www/xiehui/admin/mail/class.smtp.php on line 89
$tomail = " XXXX@126.com";
$user = " XXXXlinux ";
$_mailSubject = "Email test example!"; // Email subject group sent to the user
$_mailBody = "Sina"; // Mail content team
sendMail($tomail,$user,$_mailSubject,$_mailBody);
?>

Experiments have proven that Yahoo's SMTP is very easy to use, but the so-called Sina one is actually not easy to use. I was stuck for a long time.

Method 4, given to the program written by socket Encapsulation class for sending emails using socket:

class sendmail{
 var $lastmessage; //Record the last response message returned
 var $lastact; //Last action in string form
 var $welcome; //Used in HELO Later, users are welcome
 var $debug; //Whether to display debugging information
 var $smtp; //smtp server
 var $port; //smtp port number
 var $fp; //socket handle
 //Send mail function
 function send_mail($smtp, $welcome="", $debug=false) {
 if(empty($smtp)) die("SMTP cannot be empty!");
        $this->smtp=$smtp;
        if(empty($welcome)) {
            $this->welcome=gethostbyaddr("localhost");
        }else
        $this->welcome=$welcome;
        $this->debug=$debug;
        $this->lastmessage="";
        $this->lastact="";
        $this->port="25";
    }
    //显示调试信息
    function show_debug($message, $inout) {
        if ($this->debug) {
            if($inout=="in"){ //响应信息
                $m='<< ';
            }else
            $m='>> ';
            if(!ereg("n$", $message))
            $message .= "";
            $message=nl2br($message);
            echo "${m}${message}";
        }
    }
    //执行传递的命令
    function do_command($command, $code) {
        $this->lastact=$command;
        $this->show_debug($this->lastact, "out");
        fputs ( $this->fp, $this->lastact );
        $this->lastmessage = fgets ( $this->fp, 512 );
        $this->show_debug($this->lastmessage, "in");
        if(!ereg("^$code", $this->lastmessage))
        return false;
        else
        return true;
    }
    //邮件发送处理
    function send( $to,$from,$subject,$message) {
        //连接服务器
        $this->lastact="connect";
        $this->show_debug("连接到SMTP 服务器: ".$this->smtp, "out");
        $this->fp = fsockopen ( $this->smtp, $this->port );
        if ( $this->fp ) {
            $this->set_socket_blocking( $this->fp, true );
            $this->lastmessage=fgets($this->fp,512);
            $this->show_debug($this->lastmessage, "in");
            if (! ereg ( "^220", $this->lastmessage ) ) {
                return false;
            }else{
                $this->lastact="HELO " . $this->welcome . "n";
                if(!$this->do_command($this->lastact, "250")){
                    fclose($this->fp);
                    return false;
                }
                $this->lastact="MAIL FROM: $from" . "n";
                if(!$this->do_command($this->lastact, "250")){
                    fclose($this->fp);
                    return false;
                }
                $this->lastact="RCPT TO: $to" . "n";
                if(!$this->do_command($this->lastact, "250")){
                    fclose($this->fp);
                    return false;
                }
                //开始发送邮件正文
                $this->lastact="DATAn";
                if(!$this->do_command($this->lastact, "354")){
                    fclose($this->fp);
                    return false;
                }
                //开始处理邮件主题头
                $head="Subject: $subjectn";
                if(!empty($subject) && !ereg($head, $message)){
                    $message = $head.$message;
                }
                //开始处理邮件From头
                $head="From: $fromn";
                if(!empty($from) && !ereg($head, $message)) {
                    $message = $head.$message;
                }
                //开始处理邮件To头
                $head="To: $ton";
                if(!empty($to) && !ereg($head, $message)) {
                    $message = $head.$message;
                }
                //处理结束串
                if(!ereg("n.n", $message))
                $message .= "n.n";
                $this->show_debug($message, "out");
                fputs($this->fp, $message);
                $this->lastact="QUITn";
                if(!$this->do_command($this->lastact, "250")){
                    fclose($this->fp);
                    return false;
                }
            }
            return true;
        }else{
            $this->show_debug("连接失败！!", "in");
            return false;
        }
    }
}
?>

Example of sending email using socket:

include ("./sendmail.class.php");
$mail = new sendmail();
$email = "Hello, this is a test email!";
 $sendmail = new send_mail("smtp.mail.126.com","PHPBOOK",true); //Display the adjustment information
if($mail->send("XXXX@126.com", "XXXX@ 126.com", "Test SOCKET email", $email)) {
 echo "Sent successfully! ";
}else{
 echo "Failed to send! ";
}
?>