无法连接到詹姆斯服务器本地主机

Question

I'm trying to connect to James server localhost, but I'm getting an exception

javax.mail.MessagingException: Could not connect to SMTP host: localhost, port:25;
 nested exception is:
            java.net.SocketException: Network is unreachable: connect
            at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1545)
            at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:453)
            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 mail.main(mail.java:78)
    Caused by: java.net.SocketException: Network is unreachable: connect
            at java.net.PlainSocketImpl.socketConnect(Native Method)
            at java.net.PlainSocketImpl.doConnect(Unknown Source)
            at java.net.PlainSocketImpl.connectToAddress(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:267)
            at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:227)
            at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1511)
            ... 7 more

The directory structure of my James Server is:

C:\apache-james-2.3.2
|
|
|
|------C:\apache-james-2.3.2\james-2.3.2
|
|------C:\apache-james-2.3.2\javamail-1.4.2
|
|------C:\apache-james-2.3.2\jaf-1.0.2

Here's the code, which is throwing an exception:

I've not changed anything in the config file of james-2.3.2 subdirectory, then why I'm getting that exception?

Here's the code, which is throwing an exception:

// imports omitted
public class mail {
    public static void main(String[] args) {
        String to = "blue@localhost";
        String from = "red@localhost";
        String subject = "Hello";
        String body = "What's up";
        if ((from != null) && (to != null) && (subject != null) && (body != null)) {
            try { // we have mail to send
                Properties props = new Properties();
                props.put("mail.host", "localhost");
                props.put("mail.smtp.auth", "true");
                props.put("mail.debug", "true");
                Session session = Session.getInstance(props, new javax.mail.Authenticator() {
                    protected PasswordAuthentication getPasswordAuthentication() {
                        return new PasswordAuthentication("red", "red");
                    }
                });
                Message message = new MimeMessage(session);
                message.setFrom(new InternetAddress(from));
                Address[] add = { new InternetAddress(to) };
                message.setRecipients(Message.RecipientType.TO, add);
                message.setSubject(subject);
                message.setContent(body, "text/plain");
                message.setText(body);
                Transport.send(message);
                System.out.println(" Your message to " + to + " was successfully sent.");
            } catch (Throwable t) {
                t.printStackTrace();
            }
        }
    }
}

Answer 1

The exception is saying that localhost is unreachable. I expect that your machine does not have its loopback network address (localhost / 127.0.0.1) correctly configured.

EDIT: I assume that you are running the client and server on the same machine. If not, you cannot use localhost / 127.0.0.1.

Answer 2

I always try to telnet to port 25 on the mailhost, to check if the server can be reached. Try to connect to 127.0.0.1 to check if James is accepting incoming connections. I presume you have checked the logs of James for errors?

Answer 3

Try using the IP address 127.0.0.1 instead of the hostname 'localhost' - maybe DNS lookup on your machine is not set up properly, so that it doesn't know what the name 'localhost' means.

Open the file C:\\Windows\\System32\\drivers\\etc\\hosts , and make sure it contains a line like this:

127.0.0.1       localhost

Also, try switching off your firewall or anti-virus software.

Answer 4

• try to start apache james as root user in linux or start as Administrator on windows. and check the server is successfully started or not on james-server.log file in logs folder

• add the host name on your hosts file

  127.0.0.1 localhost

• file placed

  on linux /etc/hosts on windows C:\\Windows\\System32\\drivers\\etc\\hosts

• and restart your server.