com.jcraft.jsch.JSchException: connection is closed by foreign host when i use jsch to connect my ftp server

Question

i want to start a Sftp server by embedding it in my java code . when i start the Sftp server and then start the client , the exception throws .

my server code

public class EmbeddedSftpServer  {
    public static  final String SERVER_BASE_DIR = System.getProperty("user.dir") + File.separator + "src";
  //  public static  final String SERVER_KEYSTORE = SERVER_BASE_DIR + File.separator + "resources" + File.separator + "ftpserver.jks";
    public static  final String SERVER_KEYSTORE= "C:\\Users\\y73wang\\IdeaProjects\\SFTPServer\\src\\main\\resources\\ftpserver.jks";
    //public static  final String SERVER_USERS = SERVER_BASE_DIR + File.separator + "resources" + File.separator + "users.properties";
    public static  final String SERVER_USERS ="C:\\Users\\y73wang\\IdeaProjects\\SFTPServer\\src\\main\\resources\\users.properties";
    //public static  final String USER_HOME_DIR = SERVER_BASE_DIR + File.separator + "SftpHomeDir" ;
    public static  final String USER_HOME_DIR = "D:\\TEST";
    public static  final String SAMPLE_FILE = "test.txt";
    public static  final String ADMIN = "admin";
    public static  final String PASSWORD = "password";
    public static  final int DEFAULT_PORT =8009;
    private final FtpServer server;

    public static EmbeddedSftpServer createDefaultServer() throws Exception {
        return  new EmbeddedSftpServer(DEFAULT_PORT,ADMIN,PASSWORD,true);
    }
    public EmbeddedSftpServer( int port, String username, String password, boolean implicitSsl ) throws Exception {
        this.server = createServer( port, username, password, implicitSsl );
    }

    private FtpServer createServer( int port, String username, String password, boolean implicitSsl ) throws FtpException {
        ListenerFactory factory = new ListenerFactory();
        factory.setPort( port );
        if ( implicitSsl ) {
            SslConfigurationFactory ssl = new SslConfigurationFactory();
            ssl.setKeystoreFile( new File( SERVER_KEYSTORE ) );
            ssl.setKeystorePassword( PASSWORD );
            // set the SSL configuration for the listener
            factory.setSslConfiguration( ssl.createSslConfiguration() );
            factory.setImplicitSsl( true );
        }

        FtpServerFactory serverFactory = new FtpServerFactory();
        // replace the default listener
        serverFactory.addListener( "default", factory.createListener() );

        PropertiesUserManagerFactory userManagerFactory = new PropertiesUserManagerFactory();

        userManagerFactory.setFile( new File( SERVER_USERS ) );
        UserManager userManager = userManagerFactory.createUserManager();
        if ( !userManager.doesExist( username ) ) {
            BaseUser user = new BaseUser();
            user.setName( username );
            user.setPassword( password );
            user.setEnabled( true );
            user.setHomeDirectory( USER_HOME_DIR );
            user.setAuthorities( Collections.<Authority>singletonList( new WritePermission() ) );
            userManager.save( user );
        }

        serverFactory.setUserManager( userManager );
        return serverFactory.createServer();
    }
    public void start() throws FtpException {
        server.start();
    }
    public void stop(){
        if (server != null){
            server.stop();
        }
    }
   public static  void main(String[] args) throws Exception {
       EmbeddedSftpServer sftpServer = new EmbeddedSftpServer(DEFAULT_PORT,"admin","admin",true);
       sftpServer.start();
   }
}

user.properties:

# Password is "admin"
ftpserver.user.admin.userpassword=21232F297A57A5A743894A0E4A801FC3
ftpserver.user.admin.homedirectory=D:/test
ftpserver.user.admin.enableflag=true
ftpserver.user.admin.writepermission=true
ftpserver.user.admin.maxloginnumber=10
ftpserver.user.admin.maxloginperip=10
ftpserver.user.admin.idletime=0
ftpserver.user.admin.uploadrate=0
ftpserver.user.admin.downloadrate=0

ftpserver.user.anonymous.userpassword=
ftpserver.user.anonymous.homedirectory=D:/test
ftpserver.user.anonymous.enableflag=true
ftpserver.user.anonymous.writepermission=false
ftpserver.user.anonymous.maxloginnumber=20
ftpserver.user.anonymous.maxloginperip=2
ftpserver.user.anonymous.idletime=300
ftpserver.user.anonymous.uploadrate=4800
ftpserver.user.anonymous.downloadrate=4800

the Client code :

public class JschClient {
public void sendFile(String filename) throws JSchException, SftpException, FileNotFoundException {
    int Port =22;
    String sftphost = "127.0.0.1";
    String userName = "admin";
    String password = "admin";
    String HomeDir = "D:\\test";
    Session session =null;
    Channel channel =null;
    ChannelSftp channelSftp = null;
    JSch jSch = new JSch();
    session =jSch.getSession(userName,sftphost,8009);
    java.util.Properties config = new java.util.Properties();
    config.put("StrictHostKeyChecking","no");
    config.put("PreferredAuthentications", "password");
    session.setConfig(config);
    session.setPassword(password);
    session.connect(60000);
    channel = session.openChannel("sftp");
    channel.connect();
    channelSftp = (ChannelSftp) channel;
    ((ChannelSftp) channel).cd(HomeDir);
    File f = new File(filename);
    channelSftp.put(new FileInputStream(f),f.getName());
    channelSftp.exit();
    System.out.println("sftp Channel exited.");
    channel.disconnect();
    System.out.println("Channel disconnected.");
    session.disconnect();
    System.out.println("Host Session disconnected.");
}
public static void main(String[]agrs) throws FileNotFoundException, JSchException, SftpException {
    JschClient jschClient = new JschClient();
    jschClient.sendFile("D:\\file1.txt");
}

error log:

Exception in thread "main" com.jcraft.jsch.JSchException: connection is closed by foreign host
at com.jcraft.jsch.Session.connect(Session.java:269)
at client.JschClient.sendFile(JschClient.java:29)
at client.JschClient.main(JschClient.java:45)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)

is there any wrong in my code ?

score 1 · Answer 1 · answered Sep 14 '16 at 06:28

1

You are starting an FTP server, but connecting to it using an SFTP client.

That cannot work. The FTP and SFTP are two completely different and incompatible protocols.

answered Sep 14 '16 at 06:28

Martin Prikryl

188,800
56
490
992

score 1 · Answer 2 · answered Jul 05 '17 at 09:04

May be i am very late to answer your question but still if anyone needs how to connect with SFTP using jsch library.

You can use below method

   static Session session = null;
    static Channel channel = null;


public Session sftpConnection(final String value, final String sftpUser, final String sftpHost, final int sftpPort,
        final String sftpPass) {
        System.out.println("preparing the host information for sftp.");
        try {
            JSch jsch = new JSch();
            this.session = jsch.getSession(sftpUser, sftpHost, sftpPort);
            if (value.equals("puttyServer")) {
                this.session.setProxy(new ProxySOCKS5("proxy need to add", Integer.parseInt("portnumber need to add")));
            }
            this.session.setPassword(sftpPass);
            java.util.Properties config = new java.util.Properties();
            config.put("StrictHostKeyChecking", "no");
            this.session.setConfig(config);
            this.session.connect();
            return this.session;
        } catch (Exception ex) {
            ex.printStackTrace();
            sftpConnection(value, sftpUser, sftpHost, sftpPort, sftpPass);
        }
        return null;
    }

I do not see how does this answer the question. – Martin Prikryl Jul 07 '17 at 15:08 — Martin Prikryl, Jul 07 '17 at 15:08

score 1 · Answer 3 · answered Jan 28 '20 at 09:31

This could be the issue of whitelisting the servers. Consider there are two servers named X and Y and You are trying to connect to Y from X using Jsch SFTP. In that case, server X should be in white list of server Y.

**************CODE BLOCK of SESSION CLASS********

while(true){
        i=0;
        j=0;
        while(i<buf.buffer.length){
          **j=io.getByte();** //io.getByte() reads the key which is shared between two servers
          if(j<0)break;
          buf.buffer[i]=(byte)j; i++; 
          if(j==10)break;
        }
        if(j<0){
          throw new JSchException("connection is closed by foreign host");
        }

score 0 · Answer 4 · answered May 30 '18 at 07:28

0

just tweak the sshd_config 'MaxStartups' count, for example 'MaxStartups 1000', and restart ssh

answered May 30 '18 at 07:28

Rinoux

11
3

com.jcraft.jsch.JSchException: connection is closed by foreign host when i use jsch to connect my ftp server

4 Answers4