CODEWITHSUNDEEP
java
yantaq
yantaq

Reputation: 4038

Java Socket Connection Via Jsch Port Forwarding

I am trying to establish socket connection by local port forwarding. the flow is:
Client --> SSHhost --> TargetHost

Trying to achieve that by port forwarding but keep getting IllegalStateException: Can't connect to rHost error.
I tested that remote host does accepts connection directly and my use case is to connect via SSHhost.

not sure where it went wrong or I am open to different approach or suggestions? Thanks.

 try {
        jsch.addIdentity(privateKeyPath);
        session = jsch.getSession(username, hostL, port);
        session.setConfig("PreferredAuthentications", "publickey,keyboard-interactive,password");
        java.util.Properties config = new java.util.Properties();
        session.setConfig(config);
    } catch (JSchException e) {
        throw new RuntimeException("Failed to create Jsch Session object.", e);
    }

    try {
        session.connect();

        session.setPortForwardingL(8080, rHost, rPort);
        try (Socket s = new Socket()) {
            s.connect(new InetSocketAddress(rHost, 8080), timeout);
        } catch (Exception e) {
            String errText = String.format("Can't connect to rHost")
            throw new IllegalStateException(errText);
        }

        session.disconnect();
    } catch (JSchException e) {
        throw new RuntimeException("Error durring session connection );
    }

Upvotes: 0

Views: 518

Answers (1)

muasif80
muasif80

Reputation: 6006

You need to change the following line

s.connect(new InetSocketAddress(rHost, 8080), timeout);

to

s.connect(new InetSocketAddress("localhost", 8080), timeout);

Because you have actually mapped your localhost port 8080 to the remote host port when you used the method session.setPortForwardingL(8080, rHost, rPort);

You can try this code

try {

            jsch.addIdentity(privateKeyPath);
            session = jsch.getSession(username, hostL, port);
            session.setConfig("PreferredAuthentications", "publickey,keyboard-interactive,password");

            session.setConfig("StrictHostKeyChecking", "no");



            session.connect();

            session.setPortForwardingL(8080, rHost, rPort);
            Socket s = new Socket();
            s.connect(new InetSocketAddress("localhost", 8080), timeout);


            session.disconnect();
        } catch (JSchException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }

Upvotes: 2

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