PHP 套接字 SMTP 握手 VRFY 电子邮件

Question

如何使用 SMTP 握手验证电子邮件地址有效/无效？我的代码总是显示无效电子邮件不存在。但实际上它是存在的。

在此代码中，我使用 SMTP 详细信息来验证收件人电子邮件是否有效。

$smtpHost = 'mail.sender.com'; // Replace with your SMTP server hostname
            $smtpPort = 587; // Use the appropriate port for your SMTP server
            $localDomain = 'sender.com'; // Replace with the name of your server
            $recipientEmail = '[email protected]'; // Replace with the recipient's email
            $username = '[email protected]';
            $password = '**********';
            list(,$domain) = explode("@",$recipientEmail);

            // Open a socket connection to the SMTP server
            $socket = fsockopen($smtpHost, $smtpPort, $errno, $errstr, 30);
            
            if (!$socket) {
                echo "Failed to open socket: $errstr ($errno)";
            } else {
                
                function readResponse($socket) {
                    $response = '';
                    do {
                        $line = fgets($socket, 512);
                        $response .= $line;
                    } while (preg_match('/^\d{3}-/', $line));
            
                    echo $response;
                    return $response;
                }
            
                // Read the initial response from the server
                $response = readResponse($socket);
            
                // Send the EHLO (or HELO) command to the SMTP server
                fputs($socket, "EHLO $localDomain\r\n"); // Use EHLO or HELO as needed
                $response = readResponse($socket);
            
                // Check if the server responds with a 250 code indicating a successful greeting
                if (preg_match('/^250/', $response)) {
                    // Send the AUTH command with your SMTP credentials (username and password)
                    $response = readResponse($socket);
                    fputs($socket, "AUTH LOGIN\r\n");
                    $response = readResponse($socket);
            
                    if (preg_match('/^334/', $response)) {
                        // Send the base64-encoded username
                        fputs($socket, base64_encode($username) . "\r\n");
                        $response = readResponse($socket);
            
                        if (preg_match('/^334/', $response)) {
                            // Send the base64-encoded password
                            fputs($socket, base64_encode($password) . "\r\n");
                            $response = readResponse($socket);
            
                            // Check if authentication was successful (usually 235 for success)
                            if (preg_match('/^235/', $response)) {
                                
                                // Send the sender's email address
                                fputs($socket, "MAIL FROM:<$username>\r\n");
                                $response = readResponse($socket);
                                
                                // Now you can send the RCPT TO command
                                fputs($socket, "RCPT TO:<$recipientEmail>\r\n");
                                $response = readResponse($socket);
                                
                                // Send VRFY command
                                fputs($socket, "VRFY $recipientEmail\r\n");
                                $response = readResponse($socket);
                                
                                // Check the response
                                if (preg_match('/^250/', $response)) {
                                    echo "The email address '$recipientEmail' exists on the server.\r\n";
                                } else {
                                    echo "The email address '$recipientEmail' does not exist or the server doesn't support VRFY.\r\n";
                                }

                                
                                // Close the connection
                                fputs($socket, "QUIT\r\n");
                                $response = readResponse($socket);
                                
                                
                            } else {
                                echo "SMTP authentication failed.\r\n";
                            }
                        } else {
                            echo "Failed to send the password.\r\n";
                        }
                    } else {
                        echo "Failed to send the username.\r\n";
                    }
                } else {
                    echo "Failed to greet the SMTP server.\r\n";
                }
            
                // Close the socket connection when done
                fclose($socket);
            }

上述代码的响应截图：

我想使用 PHP Socket SMTP Handshake 检查电子邮件地址是否有效/无效

Answer 1

VRFY 不是验证电子邮件有效/无效的好选择。我解决了这个问题，添加了对 RCPT TO 的检查。请检查以下代码

                            // Now you can send the RCPT TO command
                            fputs($socket, "RCPT TO:<$recipientEmail>\r\n");
                            $response = readResponse($socket);
                            
                            // Check the response
                            if (preg_match('/^250/', $response)) {
                                echo "The email address '$recipientEmail' is accepted by the server.\r\n";
                            } else {
                                echo "The email address '$recipientEmail' is not accepted or there was an error.\r\n";
                            }