使用云服务器，项目部署在tomcat上，发送邮件出现Invalid message received with signature 18245，修改465,

防火墙，高级设置，添加入站规则，本地端口-UDP-465

使用mailutils发送。
百度查很多说是端口问题，让加127.0.0.1，然并卵。云服务器可能会禁用25端口，所以不能使用普通的smtp发送邮件

import java.util.Properties;
import javax.mail.Authenticator;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMessage.RecipientType;

public class MailUtils 
{
	public static void sendMail(String email, String emailMsg)
			throws AddressException, MessagingException {
		// 1.创建一个程序与邮件服务器会话对象 Session
		Properties props = new Properties();
		props.setProperty("mail.transport.protocol", "SMTP");
		props.setProperty("mail.smtp.host", "smtp.163.com");
		props.setProperty("mail.smtp.auth", "true");// 指定验证为true
		props.setProperty("mail.smtp.socketFactory.fallback", "false");
        props.setProperty("mail.smtp.port", "465");
        props.setProperty("mail.smtp.socketFactory.port", "465");
        props.setProperty("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
        
/*
 *  p.setProperty("mail.smtp.host", FROM_MAIL_SMTP);
     p.setProperty("mail.smtp.socketFactory.class", SSL_FACTORY);
 
 */
		// 创建验证器   username  password 是那个通行密码
		Authenticator auth = new Authenticator() {
			public PasswordAuthentication getPasswordAuthentication() {
				return new PasswordAuthentication("username", "password");
			}
		};

		Session session = Session.getInstance(props, auth);

		// 2.创建一个Message，它相当于是邮件内容
		Message message = new MimeMessage(session);

		message.setFrom(new InternetAddress("username@163.com")); // 设置发送者

		message.setRecipient(RecipientType.TO, new InternetAddress(email)); // 设置发送方式与接收者

		message.setSubject("用户激活");
		// message.setText("这是一封激活邮件，请<a href='#'>点击</a>");

		message.setContent(emailMsg, "text/html;charset=utf-8");

		// 3.创建 Transport用于将邮件发送

		Transport.send(message);
	}
}