When using Java Apache FTPClient for FTP TLS getting “Remote host closed connection during handshake” [duplicate]

Answer 1

The important information is not the exception message itself, but this message in the log:

450 TLS session of data connection has not resumed or the session does not match the control connection

Some FTP servers do require that you reuse the TLS session for data connections.

This is not (yet) natively supported by Apache Commons Net library, but it's not difficult to implement it.

How to do that, is shown in my answer to:
How to connect to FTPS server with data connection using same TLS session?

Answer 2

I have Solved this problem using Cyberduck library. https://github.com/iterate-ch/cyberduck
first why this Handshake problem arises, because some advances FTP servers allow only one session for connection and data transmission.

1)Control Session - > for connection
2)Data Session - > data storage/download/etc

So how to solve this.

Step 1 -:

First You need to checkout cyberduck repo from GitHub. from here - : https://github.com/iterate-ch/cyberduck

Step 2 -: You will see FTP and core module in checkout repo ftp and core modules

Step 3 -: Convert this module into maven and create jar for the same.

Step 4 -: add this jar into you project, but this jar also requires other dependencies so add those accordingly into project build path as well.

Step 5 -: Code snippet.

public class TestFTPS {
    public static void main(String[] args) throws SocketException, IOException {
        TrustManager[] trustManagers = new TrustManager[] { new X509TrustManager() {
            @Override
            public X509Certificate[] getAcceptedIssuers() {
                // TODO Auto-generated method stub
                return null;
            }
            @Override
            public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {
                // TODO Auto-generated method stub
            }

            @Override
            public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
                // TODO Auto-generated method stub
            }
        } };
        SSLContext sslContext = null;
        try {
            sslContext = SSLContext.getInstance("SSL");
            sslContext.init(null, trustManagers, new SecureRandom());
        } catch (Exception e) {
            e.printStackTrace();
        }
        SSLSocketFactory sslSocketFactory = sslContext.getSocketFactory();
        Protocol protocol = new FTPTLSProtocol();
        FTPClient client = new FTPClient(protocol, sslSocketFactory, sslContext);
        client.addProtocolCommandListener(new PrintCommandListener(new PrintWriter(System.out)));
        client.connect(ftphostname, port);
        client.execAUTH("TLS"); //SSL
        System.out.println(client.getReplyCode());
        if (client.login(username, password)) {
            client.execPBSZ(0);
            client.execPROT("P");
            String date = "Testing Data Send to provide FTP location";
            client.setFileType(FTP.BINARY_FILE_TYPE);
            client.enterLocalPassiveMode();
            InputStream is = new ByteArrayInputStream(date.getBytes());
            client.storeFile("test.txt", is);
            System.out.print(client.getReplyCode());
        }
    }
}

Step 6 -: After running this code, your file will be transferred successfully to ftp location.

Note - :Please add required jar in your project

Hope This will help you.