[JSch-users] Remote Port Forwarding gives exception

[Bernd R. <ber...@ca...>]

Hi all.

 

I have a problem with Jsch for remote port forwarding. I set up a
connection without problems. Local port forwarding works as well. 

 

But when using remote port forwarding:

session.setPortForwardingR(778, "localhost", 3306);

 

I get an exception: 

Caused by: com.jcraft.jsch.JSchException: remote port forwarding failed
for listen port 778

      at com.jcraft.jsch.Session.setPortForwarding(Session.java:1658)

      at com.jcraft.jsch.Session.setPortForwardingR(Session.java:1597)

      at com.jcraft.jsch.Session.setPortForwardingR(Session.java:1587)

      at
com.camunda.bpp.gatekeeper.agents.SshAgent.start(SshAgent.java:47)

 

Anybody any idea? 

 

When I use remote port forwarding via Putty or another SSH client, it
works fine, so it must be a problem with Jsch. Any help would be
appreciated!

 

By the way, the Exception is thrown because of a reply=0 (whatever that
means?):

 

  private void setPortForwarding(String bind_address, int rport) throws
JSchException{

    synchronized(grr){

    Buffer buf=new Buffer(100); // ??

    Packet packet=new Packet(buf);

 

    String address_to_bind=ChannelForwardedTCPIP.normalize(bind_address);

 

    try{

      // byte SSH_MSG_GLOBAL_REQUEST 80

      // string "tcpip-forward"

      // boolean want_reply

      // string  address_to_bind

      // uint32  port number to bind

      packet.reset();

      buf.putByte((byte) SSH_MSG_GLOBAL_REQUEST);

      buf.putString("tcpip-forward".getBytes());

//      buf.putByte((byte)0);

      buf.putByte((byte)1);

      buf.putString(address_to_bind.getBytes());

      buf.putInt(rport);

      write(packet);

    }

    catch(Exception e){

      if(e instanceof Throwable)

        throw new JSchException(e.toString(), (Throwable)e);

      throw new JSchException(e.toString());

    }

 

    grr.setThread(Thread.currentThread());

    try{ Thread.sleep(10000);}

    catch(Exception e){

    }

    int reply=grr.getReply();

    grr.setThread(null);

    if(reply==0){

      throw new JSchException("remote port forwarding failed for listen
port "+rport);

    }

    }

  }

 

Cheers

Bernd