在我的Windows 7系统上发送测试电子邮件时，总共有非常长的延迟 20秒。我已经尝试过不同的smtp服务器实现（jsmtpd，subethasmtp），但两者都显示相同的延迟。在Linux系统上运行相同的测试没有延迟。这是一个Windows localhost网络问题吗？
我的示例代码：
import javax.mail.Message;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.core.config.DefaultConfiguration;
import org.springframework.mail.javamail.JavaMailSenderImpl;
import org.springframework.mail.javamail.MimeMessagePreparator;
import org.subethamail.wiser.Wiser;
public class C_MailerTest {
public static void main( String[] args ) {
System.setProperty( DefaultConfiguration.DEFAULT_LEVEL, Level.DEBUG.name() );
Wiser wiser = new Wiser();
wiser.start();
MimeMessagePreparator preparator = new MimeMessagePreparator() {
@Override
public void prepare(MimeMessage mimeMessage) throws Exception {
mimeMessage.setRecipient( Message.RecipientType.TO, new InternetAddress( "mail@yourcompany.com" ) );
mimeMessage.setFrom( new InternetAddress( "mail@mycompany.com" ) );
mimeMessage.setText( "test" );
}
};
JavaMailSenderImpl sender = new JavaMailSenderImpl();
sender.setHost( "127.0.0.1" );
System.out.println( "sending mail" );
sender.send(preparator);
System.out.println( "mails received: " + wiser.getMessages().size() );
wiser.stop();
}
}
以下是日志（Windows 7企业版，Service Pack 1）：
09:36:04.340 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: AUTH
09:36:04.341 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: DATA
09:36:04.341 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: EHLO
09:36:04.341 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: HELO
09:36:04.341 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: HELP
09:36:04.341 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: MAIL
09:36:04.341 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: NOOP
09:36:04.341 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: QUIT
09:36:04.341 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: RCPT
09:36:04.341 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: RSET
09:36:04.341 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: STARTTLS
09:36:04.341 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: VRFY
sending mail
09:36:04.444 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - SMTP connection count: 1
09:36:04.451 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Server: 220 SWE-JPW.intern.src ESMTP SubEthaSMTP
09:36:04.455 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Client: EHLO SWE-JPW.intern.src
09:36:04.461 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Server: 250-SWE-JPW.intern.src
250-8BITMIME
250-STARTTLS
250-AUTH PLAIN LOGIN
250 Ok
09:36:04.481 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Client: MAIL FROM:<mail@mycompany.com>
09:36:04.481 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Server: 250 Ok
09:36:04.484 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Client: RCPT TO:<mail@yourcompany.com>
09:36:04.484 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Server: 250 Ok
09:36:09.495 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Client: NOOP
09:36:09.495 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Server: 250 Ok
09:36:14.495 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Client: NOOP
09:36:14.495 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Server: 250 Ok
09:36:19.495 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Client: NOOP
09:36:19.495 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Server: 250 Ok
09:36:24.049 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Client: DATA
09:36:24.049 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Server: 354 End data with <CR><LF>.<CR><LF>
09:36:24.051 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Server: 250 Ok
09:36:24.055 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Client: QUIT
09:36:24.055 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Server: 221 Bye
mails received: 1
09:36:24.058 [org.subethamail.smtp.server.SMTPServer] INFO org.subethamail.smtp.server.SMTPServer - SMTP Server socket shut down.
有很多NOOP日志条目延迟了5秒钟。
在linux机器上运行相同测试的日志（ubuntu）：
09:53:55.312 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: AUTH
09:53:55.313 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: DATA
09:53:55.313 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: EHLO
09:53:55.313 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: HELO
09:53:55.313 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: HELP
09:53:55.314 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: MAIL
09:53:55.314 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: NOOP
09:53:55.314 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: QUIT
09:53:55.314 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: RCPT
09:53:55.314 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: RSET
09:53:55.314 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: STARTTLS
09:53:55.314 [main] DEBUG org.subethamail.smtp.server.CommandHandler - Added command: VRFY
sending mail
09:53:55.395 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - SMTP connection count: 1
09:53:55.397 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Server: 220 vm-gkls ESMTP SubEthaSMTP
09:53:55.399 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Client: EHLO vm-gkls
09:53:55.402 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Server: 250-vm-gkls
250-8BITMIME
250-STARTTLS
250-AUTH PLAIN LOGIN
250 Ok
09:53:55.422 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Client: MAIL FROM:<mail@mycompany.com>
09:53:55.422 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Server: 250 Ok
09:53:55.423 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Client: RCPT TO:<mail@yourcompany.com>
09:53:55.423 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Server: 250 Ok
09:53:55.423 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Client: DATA
09:53:55.423 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Server: 354 End data with <CR><LF>.<CR><LF>
09:53:55.426 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Server: 250 Ok
09:53:55.427 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Client: QUIT
09:53:55.427 [org.subethamail.smtp.server.ConnectionHandler] DEBUG org.subethamail.smtp.server.ConnectionHandler - Server: 221 Bye
mails received: 1
09:53:55.429 [org.subethamail.smtp.server.SMTPServer] INFO org.subethamail.smtp.server.SMTPServer - SMTP Server socket shut down.
在Linux系统上绝对没有延迟。程序立即发送和接收邮件。
环境：