JavaMail 连接问题

JavaMail connection problems

提问by klib

I am trying to test a simple program found online to send an email using JavaMail. I am attempting to use a work email but I get an error "Could not connect to SMTP host:..." and "Permission denied: connect". I have looked through other posts on this issue including:

我正在尝试测试一个在网上找到的使用 JavaMail 发送电子邮件的简单程序。我正在尝试使用工作电子邮件，但收到错误“无法连接到 SMTP 主机：...”和“权限被拒绝：连接”。我浏览了有关此问题的其他帖子，包括：

JavaMail Exchange Authentication

JavaMail 交换认证

Sending email using JSP

使用 JSP 发送电子邮件

JavaMail API to iMail -- java.net.SocketException: Permission denied: connect

JavaMail API 到 iMail -- java.net.SocketException: 权限被拒绝：连接

I think I have addressed the problems mentioned in the solutions of those posts which are basically the IPv4 issue and the authentication. I am new to attempting to using JavaMail so I wonder if I am making some other beginner mistake. Are there any other things I am overlooking? Is it possible I just do not have access to the server in this manner? I have used generic names not the actual name of my company.

我想我已经解决了那些帖子的解决方案中提到的问题，这些问题基本上是 IPv4 问题和身份验证。我是尝试使用 JavaMail 的新手，所以我想知道我是否犯了其他一些初学者错误。还有其他我忽略的东西吗？是否有可能我只是无法以这种方式访问​​服务器？我使用的通用名称不是我公司的实际名称。

The code is below:

代码如下：

public static void main(String[] args) 
{   
    System.setProperty("java.net.preferIPv4Stack" , "true");
    String host="mail.company.com";   
    final String user="[email protected]";//change accordingly   
    final String password="XXXXXXXX";//change accordingly   

    String to="[email protected]";//change accordingly   

    //Get the session object   
    Properties props = new Properties();   
    props.put("mail.smtp.host",host);   
    props.put("mail.smtp.auth", "true");   

    Session session = Session.getDefaultInstance(props, new javax.mail.Authenticator() 
    {   
        protected PasswordAuthentication getPasswordAuthentication() 
        {   
            return new PasswordAuthentication(user,password);   
        }   
    });   

    //Compose the message   
    try 
    {   
        MimeMessage message = new MimeMessage(session);   
        message.setFrom(new InternetAddress(user));   
        message.addRecipient(Message.RecipientType.TO,new InternetAddress(to));   
        message.setSubject("javatpoint");   
        message.setText("This is simple program of sending email using JavaMail API");   

        //send the message   
        Transport.send(message);   

        System.out.println("message sent successfully...");   

    } 
    catch (MessagingException e) 
    {
        e.printStackTrace();
    }
}

Stack Trace:

堆栈跟踪：

javax.mail.MessagingException: Could not connect to SMTP host: mail.company.com, port: 25;
nested exception is:
java.net.SocketException: Permission denied: connect
at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1706)
at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:525)
at javax.mail.Service.connect(Service.java:313)
at javax.mail.Service.connect(Service.java:172)
at javax.mail.Service.connect(Service.java:121)
at javax.mail.Transport.send0(Transport.java:190)
at javax.mail.Transport.send(Transport.java:120)
at mailtesting.SendMailBySite.main(SendMailBySite.java:45)

Caused by: java.net.SocketException: Permission denied: connect
at java.net.TwoStacksPlainSocketImpl.socketConnect(Native Method)
at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:284)
at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:227)
at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1672)
... 7 more

采纳答案by klib

java.net.SocketException: Permission denied: connect

This means you connected to the server and port and the server actively deniedyour connection.

这意味着您连接到服务器和端口，服务器主动拒绝了您的连接。

If you try and telnetto this server and port you might get a more descriptive message, either way, that port isn't going to work.

如果您尝试telnet访问此服务器和端口，您可能会收到更具描述性的消息，无论哪种方式，该端口都不会工作。

Most likely that port 25is blocked as a security measure, this is pretty standard settings for most companies.

很可能该端口25被阻止作为安全措施，这对于大多数公司来说是非常标准的设置。

Since you are using Outlook can't find the port in the settings, I am assuming you are connecting to an Exchange server, which might not even have SMTPenabled at all if your entire company is a Microsoft Outlook shop.

由于您使用的 Outlook 无法在设置中找到端口，我假设您正在连接到 Exchange 服务器，SMTP如果您的整个公司都是 Microsoft Outlook 商店，则该服务器甚至可能根本没有启用。

You will need to contact your system admin team to find out what port and protocol you should actually be using.

您需要联系您的系统管理员团队以了解您实际应该使用的端口和协议。