Sockets won't work in network

Question

I am working on an application that sends files via the network.

I used 2 classes to send and to receive the file that I selected.

The problem that I have faced, when I am working on localhost, is that the process goes correctly, but when I change the IP address to the network IP, it does not work.

Here is the two classes that I am using.

Class Server :

    package Test;

    import java.io.BufferedInputStream;
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.IOException;
    import java.io.OutputStream;
    import java.net.ServerSocket;
    import java.net.Socket;

    public class Server{
 public static void main (String [] args ) throws IOException {
// create socket
ServerSocket servsock = new ServerSocket(41111);
while (true) {
  System.out.println("Waiting...");

  Socket sock = servsock.accept();
  System.out.println("Accepted connection : " + sock);

  // sendfile
  File myFile = new File ("C:\\Users\\Marrah.Zakaria\\Desktop\\test\\test.txt");
  byte [] mybytearray  = new byte [(int)myFile.length()];
  FileInputStream fis = new FileInputStream(myFile);
  BufferedInputStream bis = new BufferedInputStream(fis);
  bis.read(mybytearray,0,mybytearray.length);
  OutputStream os = sock.getOutputStream();
  System.out.println("Sending...");
  os.write(mybytearray,0,mybytearray.length);
  os.flush();
  sock.close();
  }
}
}

Class Client:

 package Test;

 import java.io.BufferedOutputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.Socket;


 public class Client{
 public static void main (String [] args ) throws IOException {
 int filesize=6022386; // filesize temporary hardcoded

 long start = System.currentTimeMillis();
 int bytesRead;
 int current = 0;

Socket sock = new Socket("192.168.1.100",41111);
System.out.println("Connecting...");

 // receive file
 byte [] mybytearray  = new byte [filesize];
 InputStream is = sock.getInputStream();
 FileOutputStream fos = new FileOutputStream("C:\\Test\\test-copy.txt");
 BufferedOutputStream bos = new BufferedOutputStream(fos);
 bytesRead = is.read(mybytearray,0,mybytearray.length);
 current = bytesRead;


do {
   bytesRead =
      is.read(mybytearray, current, (mybytearray.length-current));
   if(bytesRead >= 0) current += bytesRead;
} while(bytesRead > -1);

bos.write(mybytearray, 0 , current);
bos.flush();
long end = System.currentTimeMillis();
System.out.println(end-start);
bos.close();
sock.close();
sock.getPort();
}
}

after running an exception shows up :

Exception in thread "main" java.net.ConnectException: Connection timed out: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at            java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:69)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:157)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:391)
at java.net.Socket.connect(Socket.java:579)
at java.net.Socket.connect(Socket.java:528)
at java.net.Socket.<init>(Socket.java:425)
at java.net.Socket.<init>(Socket.java:208)

Please would you tell me what shall i do to get rid of it.

I dis-activated the receivers firewall a different exception occurred :

 Exception in thread "main" java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:69)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:157)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:391)
at java.net.Socket.connect(Socket.java:579)
at java.net.Socket.connect(Socket.java:528)
at java.net.Socket.<init>(Socket.java:425)
at java.net.Socket.<init>(Socket.java:208)

This is probably a network issue. Can you ping the machines where this is not working (from each other)? — Bill the Lizard, Oct 09 '12 at 14:21
When switching from localhost to over network and encountering issues, I normally try to verify the two hosts can communicate with each other. Try pinging the hosts from each other first. — Lipongo, Oct 09 '12 at 14:21
I did that already, it appears that my machine recognize the receiver machine. — Zakaria Marrah, Oct 09 '12 at 14:26
Were you able to solve the issue? If yes please do share it with me because i am facing similar problem. — Nitesh Verma, Aug 01 '13 at 06:41

score 2 · Answer 1 · answered Oct 09 '12 at 14:22

2

If you start up the server, can you telnet to this combination ?

telnet 192.168.1.100 41111

That'll tell you immediately if you have a routing issue (telnet will refuse to connect)

answered Oct 09 '12 at 14:22

Brian Agnew

268,207
37
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440

what do you mean by that telnet? :D – Zakaria Marrah Oct 09 '12 at 14:57

mkhelif · Answer 2 · 2012-10-09T15:21:04.513

1

Have you check if there is any firewall blocking the custom port (41111) on your network (also check Windows firewall)?

This is the first thing to check when you have a timeout.

edited Oct 09 '12 at 15:21

answered Oct 09 '12 at 14:21

mkhelif

1,551
10
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I dis-activated it but the same exception occurs. – Zakaria Marrah Oct 09 '12 at 14:30
@ZakariaMarrah Once the firewall is deactivated and if you receive a connection refused, it means that the server is not listening on the port. Is the server started on the machine? Do you have any exception on server-side? – mkhelif Oct 09 '12 at 15:21
No, my server is started. What i did is that i turned the server's firewall off and then the connectionrefused Exception showed up. – Zakaria Marrah Oct 09 '12 at 15:36
Is there any other suggestion other then sockets to send a file via network ?? – Zakaria Marrah Oct 09 '12 at 15:40

score 1 · Answer 3 · answered Oct 09 '12 at 14:27

1

also try to ping 192.168.1.100 from the machine where you are running the client (i.e from the command prompt if you are in windows box)

answered Oct 09 '12 at 14:27

Rohini Kumar

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Sockets won't work in network

3 Answers3