Unable to connect to an SMTP server

Question

I want to basically send an email via my C# program using SMTPClient , MailAddress and MailMessage Classes. It works fine with gmail etc, but I want to use another SMTP server.

Here is my C# code sample:

SmtpClient smtpclient = new SmtpClient();
        smtpclient.Host = "STMPserver";
        smtpclient.Port = 465;
        NetworkCredential myCredentials = new NetworkCredential("username","password");
        smtpclient.Credentials = myCredentials;
        smtpclient.EnableSsl = true;
        MailAddress mailaddressfrom = new MailAddress("email", "sendername");
        MailAddress mailaddressto = new MailAddress("email", "receivername");
        MailMessage message = new MailMessage(mailaddressfrom, mailaddressto);
        smtpclient.Send(message);

What I don't get is that I fetched the information through my Android e-mail app and I entered exactly the same features for SMTPserver, Port #, username, password... It works fine with my phone but times out with my program. I probably don't give enough information or it might be possible that there is a proxy before the SMTP server, actually I don't have any idea, but I am really stuck. I also did a tracert on my cmd prompt and it turned out that I can't reach the SMTP server I want. Any help would be appreciated.

Answer 1

ADD 3 jars found in the following link to your Android Project

http://javamail-android.googlecode.com/files/mail.jar , activation.jar, additionnal.jar

How to add External Jars https://stackoverflow.com/a/6859020/28557 Run the project and check your recipient mail account for the mail. Cheers!!

Hope this helps

PS And don't forget that you cannot do network operation from the any UI activity in android. Hence it is recommended to use AsyncTask to avoid network on main thread exception.

MailSenderActivity.java

YOUR PACKAGE;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;

public class MailSenderActivity extends Activity {

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        final Button send = (Button) this.findViewById(R.id.send);
        send.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {
                // TODO Auto-generated method stub

                try {   
                    GMailSender sender = new GMailSender("username@gmail.com", "password");
                    sender.sendMail("This is Subject",   
                            "This is Body",   
                            "user@gmail.com",   
                            "user@yahoo.com");   
                } catch (Exception e) {   
                    Log.e("SendMail", e.getMessage(), e);   
                } 

            }
        });

    }
}

GmailSender.java

YOUR PACKAGE;

import javax.activation.DataHandler;   
import javax.activation.DataSource;   
import javax.mail.Message;   
import javax.mail.PasswordAuthentication;   
import javax.mail.Session;   
import javax.mail.Transport;   
import javax.mail.internet.InternetAddress;   
import javax.mail.internet.MimeMessage;   
import java.io.ByteArrayInputStream;   
import java.io.IOException;   
import java.io.InputStream;   
import java.io.OutputStream;   
import java.security.Security;   
import java.util.Properties;   

public class GMailSender extends javax.mail.Authenticator {   
    private String mailhost = "smtp.gmail.com";   
    private String user;   
    private String password;   
    private Session session;   

    static {   
        Security.addProvider(new com.provider.JSSEProvider());   
    }  

    public GMailSender(String user, String password) {   
        this.user = user;   
        this.password = password;   

        Properties props = new Properties();   
        props.setProperty("mail.transport.protocol", "smtp");   
        props.setProperty("mail.host", mailhost);   
        props.put("mail.smtp.auth", "true");   
        props.put("mail.smtp.port", "465");   
        props.put("mail.smtp.socketFactory.port", "465");   
        props.put("mail.smtp.socketFactory.class",   
                "javax.net.ssl.SSLSocketFactory");   
        props.put("mail.smtp.socketFactory.fallback", "false");   
        props.setProperty("mail.smtp.quitwait", "false");   

        session = Session.getDefaultInstance(props, this);   
    }   

    protected PasswordAuthentication getPasswordAuthentication() {   
        return new PasswordAuthentication(user, password);   
    }   

    public synchronized void sendMail(String subject, String body, String sender, String recipients) throws Exception {   
        try{
        MimeMessage message = new MimeMessage(session);   
        DataHandler handler = new DataHandler(new ByteArrayDataSource(body.getBytes(), "text/plain"));   
        message.setSender(new InternetAddress(sender));   
        message.setSubject(subject);   
        message.setDataHandler(handler);   
        if (recipients.indexOf(',') > 0)   
            message.setRecipients(Message.RecipientType.TO, InternetAddress.parse(recipients));   
        else  
            message.setRecipient(Message.RecipientType.TO, new InternetAddress(recipients));   
        Transport.send(message);   
        }catch(Exception e){

        }
    }   

    public class ByteArrayDataSource implements DataSource {   
        private byte[] data;   
        private String type;   

        public ByteArrayDataSource(byte[] data, String type) {   
            super();   
            this.data = data;   
            this.type = type;   
        }   

        public ByteArrayDataSource(byte[] data) {   
            super();   
            this.data = data;   
        }   

        public void setType(String type) {   
            this.type = type;   
        }   

        public String getContentType() {   
            if (type == null)   
                return "application/octet-stream";   
            else  
                return type;   
        }   

        public InputStream getInputStream() throws IOException {   
            return new ByteArrayInputStream(data);   
        }   

        public String getName() {   
            return "ByteArrayDataSource";   
        }   

        public OutputStream getOutputStream() throws IOException {   
            throw new IOException("Not Supported");   
        }   
    }   
}  

JSSE Provider

/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

/**
 * @author Alexander Y. Kleymenov
 * @version $Revision$
 */


import java.security.AccessController;
import java.security.Provider;

public final class JSSEProvider extends Provider {

    public JSSEProvider() {
        super("HarmonyJSSE", 1.0, "Harmony JSSE Provider");
        AccessController.doPrivileged(new java.security.PrivilegedAction<Void>() {
            public Void run() {
                put("SSLContext.TLS",
                        "org.apache.harmony.xnet.provider.jsse.SSLContextImpl");
                put("Alg.Alias.SSLContext.TLSv1", "TLS");
                put("KeyManagerFactory.X509",
                        "org.apache.harmony.xnet.provider.jsse.KeyManagerFactoryImpl");
                put("TrustManagerFactory.X509",
                        "org.apache.harmony.xnet.provider.jsse.TrustManagerFactoryImpl");
                return null;
            }
        });
    }
}

Add this line in your manifest:

<uses-permission android:name="android.permission.INTERNET" />