I have problems using Sockets on Android. I'm new to this topic so I try to achieve a simple chat, Android phone to another Android phone as a training.
I can use my code to create a ServerSocket and connect to it with another Socket from the same device ( An 'echo' example with only one client on one device works fine) I've done that also using two IP adresses on the same wifi (192.168...) but any tentative to connect a distant client using internet ip address using 3G connection fails with a
java.net.SocketException: recvfrom failed: ETIMEDOUT (Connection timed out)
What I do is, creating the ServerSocket (ServerConnect.java) :
private ServerSocket _mainServer = null;
private void initServer() {
try {
//port I use here is arbitrary: 8081
_mainServer = new ServerSocket(CONNECT_SOCKET_PORT);
} catch (IOException e) {
Log.w("ServerSocket", e.toString());
e.printStackTrace();
}
}
in the same class, in a separate thread I do this to wait for client connections :
while (running) {
GuestConnect ssc = new GuestConnect(_mainServer.accept());
ssc.setListener(this);
ssc.startConnection();
_clientSockets.add(ssc);
performGuestAdded("bra!");
}
it makes the server waiting for multiple client connection, so it can host more than two poeple in the 'chat room'.
The comunication server side is made from the local client callback and dispatch messages to all my guests (I'm still working on this part, its not really done yet but I don't think its relevant to my problem here) :
public void onMessageReceived(TBTGuestConnect sender, String message) {
for(TBTGuestConnect guestConnect : _clientSockets)
if(guestConnect != sender)
guestConnect.sendMessage(message);
}
Clients are store as 'GuestConnect' objects here is how I set them (GuestConnect.java):
public class GuestConnect {
private StringBuilder _currentMessage;
private BufferedReader _is;
private PrintStream _os;
private Socket _clientSocket = null;
private String _hostname;
private boolean _running = false;
public GuestConnect(String hostname) {
_hostname = hostname;
_currentMessage = new StringBuilder();
}
clientSocket initialisation (still GuestConnect.java):
private void initSocket() {
if(_clientSocket==null)
{
// Try to open a server socket on given port
// Here is the fail when I called it from another device
try {
_clientSocket = new Socket(_hostname, ServerConnect.CONNECT_SOCKET_PORT);
} catch (IOException e) {
Log.w("GuestSocket", e.toString());
}
}
// Create a socket object from the ServerSocket to listen and accept
// connections.
// Open input and output streams
try {
_is = new BufferedReader(new InputStreamReader(_clientSocket.getInputStream()));
_os = new PrintStream(_clientSocket.getOutputStream());
} catch (IOException e) {
Log.w("GuestSocket", e.toString());
}
}
again, in the same class there is the comunication part :
initSocket();
_running = true;
performConnectionStarted();
try {
while (_running) {
String received = _is.readLine();
_currentMessage.append(received);
if (received.contains(ServerConnect.CONNECT_SOCKET_MESSAGE_END)) {
String finalMsg = _currentMessage.toString().substring(0, _currentMessage.lastIndexOf(ServerConnect.CONNECT_SOCKET_MESSAGE_END));
performMessageReceived(finalMsg);
_currentMessage.setLength(0);
}
}
} catch (IOException e) {
Log.w("GuestSocket", e.toString());
performError(e);
} finally {
try {
_os.close();
_is.close();
_clientSocket.close();
} catch (IOException e) {
e.printStackTrace();
performError(e);
}
_clientSocket = null;
}
I can then send a message from this method :
public void sendMessage(String toSend) {
if (_running)
_os.println(toSend+ServerConnect.CONNECT_SOCKET_MESSAGE_END);
else
throw new IllegalStateException("Send message : Connection isn't started !");
}
So the question is, what should I do to make this works using global internet ip addresses ?
And more generally, what it the technical difference between same wifi local ip address and internet ip adress ?
i'll start from the end because it's easier - local ip address is private, it's not valid (and not visible) out of your local network, someone out of your local network can't access it directly but you can access hosts with public ip addresses. because they are not universally visible private addresses are not unique, public ip addresses are unique and (normally) visible from any point on the internet. there's more on the subject http://en.wikipedia.org/wiki/Network_address_translation
when it comes to 3g networks take a look here Could I connect to my iphone using 3g ip? and here ServerSocket accept() not accepting connections on Android . so most probably it can't be done
Don't know if this would be of any importance to you but in our country most 3G accounts are blocked by the ISP from incoming connections. You have to apply to unblock the ports. Some ISP's won't unblock them and some will.
Found that out when I wanted to connect my DVR with a 3G modem.
Related
I have written a client to run on an android device (android 6) and when the server is up and running it connects, however when the server is down the socket() call should throw an exception however it doesn't.
I originally tried it using the NDK and ran into a very similar issue (Android NDK socket connect() returning 0 when it should fail whilst on 3g).
I am assuming this is a bug with android at this point but any insight into a solution or work around would be much appreciated.
The code in question:
public class Client implements Runnable{
private Socket socket;
private InetAddress IP;
private int port;
public Client(int port){
try {
this.IP = InetAddress.getByName(server ip);
}
catch(UnknownHostException e){
Log.d("App1", "Unknown Host, connection failed");
System.exit(1);
}
this.port = port;
Log.d("App1", "initialised");
}
#Override
public void run(){
try {
this.socket = new Socket(this.IP, this.port);
Log.d("FiX1", "Connected");
listen();
}
catch(IOException e){
Log.d("FiX1,","connection failed");
System.exit(1);
}
finally
{
try{
socket.close(); // dispose
}
catch(IOException e){
System.exit(1);
}
}
}
public void listen() {
try {
BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
while (true) {
String cominginText = "";
try {
cominginText = in.readLine();
Log.d("FiX1",cominginText);
} catch (IOException e) {
//error ("System: " + "Connection to server lost!");
System.exit(1);
break;
}
}
} catch (IOException e) {
System.exit(1);
}
}
}
The best solution I could find was to manually send an acknowledgement from the server that a connection had been made, the client would retry the connection if it did not receive this message within a certain time after it claimed to have connected.
There is a difference between a TCP connection "close" vs "disconnect".
If you close the socket connection from server using socket.close() then you will get exception in client side, if you try to read from that connection or vice versa.
However, if one side just disappears(shut down the program) then the other side has no way of knowing that. So the other side will wait for response for read call.
The TCP protocol was designed to be reliable in hostile communication environments and it will not normally decide a connection is closed just because it has not heard from the other side for a while.
EDIT: I have corrected the mistake below in the code, by adding a line into the server code
I'm trying to write some socket code that will allow me to send data from one computer to another for a game (which for simplicity's sake, we can think of as tic-tac-toe, not much data needs to be sent, just a couple of numbers). In order to achieve this I have written two classes, Server and Client. At the moment I am testing through the localhost using port 1234, and I am only using one single instance of the program (though the same problem occurs when trying to use two instances).
Firstly here's the code, and then I can go into more depth about the problem, and what testing I've done to attempt to work out what is going wrong:
public class Server
{
private ServerSocket server;
private Socket socket;
private Client socketHandler;
private static final int DEFAULT_PORT = 1234;
public Server() { this(DEFAULT_PORT); }
public Server(int port)
{
Thread thread = new Thread()
{
public void run()
{
try
{
System.out.println("Attempting to Establish Connection");
server = new ServerSocket(port);
socket = server.accept();
socketHandler = new Client(port, socket); //THIS LINE ADDED
System.out.println("Server Online!");
}
catch (Exception e)
{
e.printStackTrace();
}
}
};
thread.setDaemon(true);
thread.start();
}
//ADJUSTED
Client getSocketHandler()
{
return socketHandler;
}
public void kill()
{
try
{
if (socket != null) socket.close();
if (server != null) server.close();
}
catch(IOException e)
{
e.printStackTrace();
}
finally
{
socket = null;
server = null;
}
}
}
public class Client
{
public static final int DEFAULT_PORT = 1234;
public static final String DEFAULT_HOST = "localhost";
private static final String THUMP_THUMP = "thump thump";
private static final int PULSE = 1000;
private int port;
private String ip;
private Socket socket;
private BufferedReader input = null;
private PrintWriter output = null;
boolean closed = true;
String data = "";
public Client() { this(DEFAULT_PORT, DEFAULT_HOST, null); }
public Client(int port) { this(port, DEFAULT_HOST, null); }
public Client(int port, String ip) { this(port, ip, null); }
public Client(int port, Socket server) { this(port, DEFAULT_HOST, server); }
public Client(String ip) { this(DEFAULT_PORT, ip, null); }
public Client(String ip, Socket server) { this(DEFAULT_PORT, ip, server); }
public Client(Socket server) { this(DEFAULT_PORT, DEFAULT_HOST, server); }
public Client(int port, String ip, Socket server)
{
socket = server;
this.ip = ip;
this.port = port;
Thread thread = new Thread()
{
public void run()
{
try
{
initialise(server);
String line;
startHeartbeat();
while (isClosed()) {} //first it is closed, lets wait for it to open before we start waiting for it to close!
System.out.println("We are about to listen!");
while (!isClosed())
{
System.out.println("pre-read"); //this line was used to determine that the code was hanging on the next line
line = input.readLine(); //offending line
System.out.println("post-read"); //this line was used to determine when the block was lifted
if (line != null)// || line != THUMP_THUMP)
{
System.out.println(line);
data += line + "\n";
}
}
System.out.println(data);
kill();
System.out.println("Connection Closed!");
}
catch (SocketException e)
{
e.printStackTrace();
System.out.println("Server closed!");
}
catch (Exception e)
{
e.printStackTrace();
}
}
};
thread.setDaemon(true);
thread.start();
}
private void initialise(Socket server)
{
try
{
if (server == null) socket = new Socket(ip, port);
input = new BufferedReader(new InputStreamReader(socket.getInputStream()));
output = new PrintWriter(new OutputStreamWriter(socket.getOutputStream()));
}
catch (IOException e) { e.printStackTrace(); }
}
public boolean post(String text)
{
synchronized(this)
{
output.println(text);
output.flush();
return !output.checkError();
}
}
public void kill()
{
try
{
if (input != null) input.close();
if (socket != null) socket.close();
}
catch(IOException e) { e.printStackTrace(); }
finally
{
input = null;
socket = null;
}
}
public void killOutputStream()
{
try
{
if (output != null) output.close();
}
catch (Exception e) { e.printStackTrace(); }
finally
{
output = null;
}
}
//////////////////////////////////
///////// Socket Control /////////
//////////////////////////////////
synchronized boolean isClosed()
{
return closed;
}
synchronized void setClosed(boolean b)
{
closed = b;
}
//We need to make sure that the socket is still online, to ensure the reading stops when the connection closes.
void startHeartbeat()
{
Thread heartbeat = new Thread()
{
public void run()
{
while (output != null)
{
setClosed(post(THUMP_THUMP) ? false : true); //post returns true on success
synchronized(this)
{
try
{
this.wait(PULSE);
}
catch (InterruptedException e) {}
}
}
setClosed(true);
}
};
heartbeat.setDaemon(true);
heartbeat.start();
}
}
The Problem
When the client is started (after having created the server) it fails to read any data sent through (or even the heartbeat), in fact the code does not go past line = input.readLine() in the reading thread (which is from now on called the offending line), except it seems, until the server is disconnected (see below).
Here is the order of regular testing:
Server() is called and the resulting Server is stored in the serverConnection variable then
Client(serverConnection != null ? serverConnection.getSocket() : null) is called and the new Client is stored in clientConnection.
Because we can test whether it is working using the heartbeat no other data needs to be sent, and the server is terminated by calling serverConnection.kill() and then clientConnection.killOutputStream() after letting some time elapse.
and this is the result:
Attempting to Establish Connection Server Online!
We are about to listen!
Connection Closed!
where the empty line represents the non null data received over the course of the connection, ie that there is none.
I expect this:
Attempting to Establish Connection
Server Online!
We are about to listen!
thump thump
thump thump
thump thump (and so on, every second)
Connection closed!
I spent time performing different tests by commenting out or changing the code slightly with the same testing format (except for the special case, which is number 6) and made these observations:
Observations
Only when the socket is closed and the output stream is closed, does the program move past the offending line.
When the readline() method starts to process (shortly before the heartbeat cuts it off) it detects nothing in the stream, not even THUMP_THUMP.
When the socket is closed, but the output stream is not, the readline() method starts to process, only to detect nothing, heartbeat cuts it off. No SocketException even though it would be expected.
If the socket is NOT closed, and only the output stream is closed, a SocketException is triggered, suggesting the socket is closed.
I used netstat -an in command prompt, and when the server is started the port 1234 is LISTENING. When the client connects, it is still LISTENING, implying that there is no connection.
I set up some python code to connect to itself over port 1234,
however I made a mistake in the python code, and as such the server
didn't close, and was still open. So I decided to connect the java
client to the server and see what happens. I did this by running
Client(null) which is the client code for the non-host. It
resulted in the port reading ESTABLISHED, and the python server was
echoing back the "thump thump", and the java code was successfully
reading it. No hanging, it worked perfectly.
This leads me to believe that the problem lies in the server code, as the python server was able to communicate sucessfully with the Java client, but the Java client is unable to communicate with the Java server.
Before performing this testing I had been concentrating on the Client code, believing that it was at fault. All the questions I have found here with similar symptoms (see here, here and here, among others) have turned up blank for me, having written in their solutions (most were due to the output stream not flushing, or the \n ommitted, which I have not failed to do, or the solution not fixing my problem, and so having been removed in favor of the heartbeat in this case). I originally based my code off of this article.
After 4 days of trying to figure out this problem I am at a loss for what to do... What am I missing here? Why is the Server code not working as I expect it to? If anybody needs any more clarification on my code then please ask!
As an after-note, the testing code is run through a simple minimalistic GUI written in javafx (not fxml though), whether that would be a problem or not I'm sure, I would think not, due to it working with the Python server. This code is compiled in Java 8
I'm a little confused about why you think it would go any furthur than input.readLine() considering there is no handling of inputs/outputs on the server side....
Client/Server connections are like a game of tennis, as one side serves the other must receive the ball and then serve it back(maybe with different information). Your server side must handle the input it recieves from the start heartbeat method, and then send you back a response. the input.readLine() function blocks the thread until it receives data from the other end, so yes the code stops there and waits for your server to send the "tennis ball" back. In the server class you should add an input and output stream that handle the heart beat inputs and send back a string of data to the client.
Server:
OutputStream os = socket.getOutputStream();
InputStream is = socket.getInputStream();
String response = "thump thump";
while(true){
is.read();
os.write(response.getBytes());
os.flush();
}
with this example, the client should remain unchanged and just add the above code to your server.
I'm writing an application to communicate between my smartphone and a computer using a bluetooth device.
I'm using Bluecove to manage the bluetooth on the computer, and the android API for my android device.
However, when I'm debugging, nothing happens. I think that the problem is that the UUID is wrong. I'm not sure how to get the devices to identify each other, in order to establish a connection.
I have read some other "questions" about those tags, but what I've tried didn't fix my problem:
Simple Bluetooth data receiver Android
Android: obtaining uuid of a bluetooth device
Etc...
Here's what I've written so far:
For tho android (Server) (This is the function that will make the connection)
public void connectSocket(){
blueAdapter.cancelDiscovery(); // Cancel discovery because it'll slow down the connection
final BluetoothServerSocket serverSocket;
BluetoothServerSocket sSocket= null;
try{
sSocket = blueAdapter.listenUsingRfcommWithServiceRecord("BluetoothJANE", MY_UUID);
}catch(IOException e){}
serverSocket = sSocket;
Thread acceptThread = new Thread(new Runnable() {
#Override
public void run() {
BluetoothSocket socket = null;
while(true){
try{
socket = serverSocket.accept();
}catch(IOException e){
break;
}
if(socket != null){
try{
iStream = socket.getInputStream();
oStream = socket.getOutputStream();
} catch(IOException e){}
}
}
}
});
acceptThread.start();
}
For java app on PC (This is the constructor of the class (it's on an independent thread) that will manage the bluetooth connection)
public ModuleBluetooth() {
StreamConnectionNotifier notifier = null;
StreamConnection connection = null;
try {
blueDevice = LocalDevice.getLocalDevice();
blueDevice.setDiscoverable(DiscoveryAgent.GIAC);
String url = "btspp://localhost:" + MY_UUID.toString()
+ ";name=RemoteBluetooth";
notifier = (StreamConnectionNotifier) Connector.open(url);
} catch (BluetoothStateException e) {
System.out
.println("ModuleBluetooth: Error getting the bluetooth device");
} catch (IOException e) {
}
System.out.println("waiting for connection...");
try {
connection = notifier.acceptAndOpen();
System.out.println("Conenction created");
} catch (IOException e) {
System.out.println("Can not create the connection");
}
}
Could somebody please help me? Any thoughts would be very much appreciated.
I have also tried to use some functions to acquire the UUID (in android) such as, [fetchUuidsWithSdp][2] (and the related functions) but eclipse doesn't recognize that functions (It seems that they don't exist in "my" API).
http://developer.android.com/reference/android/bluetooth/BluetoothDevice.html#fetchUuidsWithSdp%28%29
Try this example, http://luugiathuy.com/2011/02/android-java-bluetooth/ . I also had problem related to UUID, in this example, Converting UUID to 00001101-0000-1000-8000-00805F9B34FB worked out of the box. See this link: http://www.avetana-gmbh.de/avetana-gmbh/produkte/doc/javax/bluetooth/UUID.html
I'm trying to build a chat program. I wrote the code and everything worked and still works great when I'm using my computer and connecting using 127.0.0.1. I also succeeded to connect successfully between my laptop and my computer, which run on the same router. (I used an internal IP address to do this, 10.0.0.3).
Now I'm trying to make a connection between my router and other routers. And to this I'm trying to connect to an external IP address. I do the port forwarding part through my router and I also made a static IP. When I run the code I always get a "connection refused error".
Here is the code:
MainServer.java:
import java.util.*;
import java.io.*;
import java.net.*;
public class MainServer {
private ArrayList<Socket> sockets;
public MainServer() {
ServerSocket server_socket;
try {
server_socket = new ServerSocket(5005);
sockets = new ArrayList<Socket>();
System.out.println("server is now running");
while(true) {
Socket socket = server_socket.accept();
sockets.add(socket);
try {
PrintWriter writer = new PrintWriter(socket.getOutputStream());
writer.println("---you are connected to the server---\r\n");
writer.flush();
} catch(Exception e) {e.printStackTrace();}
System.out.println("server connected to " + socket.getInetAddress());
Reader reader = new Reader(socket);
Thread thread = new Thread(reader);
thread.start();
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static void main(String[] args) {
MainServer server = new MainServer();
}
class Reader implements Runnable {
Socket socket;
public Reader(Socket socket) {
this.socket=socket;
}
public void run() {
while(true) {
try {
InputStreamReader stream_reader = new InputStreamReader(socket.getInputStream());
BufferedReader reader = new BufferedReader(stream_reader);
while(true) {
String str = reader.readLine();
if(str==null)
continue;
System.out.println("message from the client " + socket.getInetAddress() + ": " + str);
send_back_message(str);
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public void send_back_message(String str) {
try {
for(Socket send_to_socket: sockets) {
PrintWriter writer = new PrintWriter(send_to_socket.getOutputStream());
writer.println(send_to_socket.getInetAddress()+ ": " + str);
writer.flush();
}
} catch(Exception e) {e.printStackTrace();}
}
}
}
Client.java:
public Client() {
frame = new JFrame();
JPanel panel = new JPanel();
chat = new JTextArea(20,40);
chat.setEditable(false);
JScrollPane scroll = new JScrollPane(chat);
text = new JTextField(32);
JButton send = new JButton("Send");
send.addActionListener(new SendButtonListener());
panel.add(scroll);
panel.add(text);
panel.add(send);
frame.getContentPane().add(panel);
frame.setSize(500,500);
frame.setVisible(true);
try {
socket = new Socket("77.126.189.65",5005);
} catch (Exception e) {
e.printStackTrace();
}
Thread thread = new Thread(new ClientReader());
thread.start();
}
public static void main(String[] args) {
Client client = new Client();
}
class SendButtonListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
try {
PrintWriter writer = new PrintWriter(socket.getOutputStream());
writer.println(text.getText());
writer.flush();
text.setText("");
} catch (IOException e1) {
e1.printStackTrace();
}
}
}
class ClientReader implements Runnable {
public void run() {
try {
InputStreamReader stream_reader = new InputStreamReader(socket.getInputStream());
BufferedReader reader = new BufferedReader(stream_reader);
while(true) {
String str = reader.readLine();
if(str==null)
continue;
chat.setText(chat.getText() + str + "\r\n" );
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
I also tried this tool. When I run the MainServer file and try the tool, I get a positive answer. I also get a positive on my own Eclipse. When my MainServer makes a successful connection, it prints a message about it using these lines:
Socket socket = server_socket.accept();
System.out.println("server connected to " + socket.getInetAddress());
So every time I'm clicking the "check" button in the tool above, I get a message in my Eclipse console (system.out.println part):
server connected to /69.163.149.200
Therefore I think the problem is probably not connected to the MainServer or the portforwading/firewall/static IP.
I also thought maybe the problem occurs because I'm trying connecting from my own router device to my own router. I will leave the MainServer file open for the next half hour so if someone can run the Client.java on his computer it will be helpful.
What you trying to do is a bit weird but it is possible.
You just need to know if your router supports NAT Loopback / NAT Reflection and activate it.
NAT-loopback
Also known as NAT-hairpinning or NAT-reflection. NAT-loopback is a
feature in many consumer routers which allows a user to connect to
its own public IP address from inside the LAN-network. This is
especially useful when a website (with domain) is hosted at that IP
address.
You won't be able to do this without configuring your router appropriately. Most routers do not allow (by default) incoming connections on their external (WAN) port. If you want to allow this, you'll need to go into your router configuration and configure it to allow connections on the external IP for the specific port you are using. Then, you'll have to configure the router to redirect that incoming connection from the external IP address/port to the internal IP address/port of your actual server.
This is frequently how online gamers set up servers in their own home. It is also how many people connect to their own internal networks from the outside world.
Before anything, set up a static IP (like 192.168.1.6) internally.
If youu want to connect via an external IP, there are two ways:
If you have a router, use port forwarding.
If you have a dongle, no need to port forward; you can directly access the server. Just give the dongle's external IP (to find that, use a what's-my-IP service like this one) and a port number (any). (Dongles are not blocked by any ISP.)
You can add your internal IP address along with your server name to /etc/hosts, for example, if you have external IP 10. 10. 123. 123, and with the server name YOURCOMPUTER_1.XXX.XXX, you want to connect inside network, you can add:
127.0.0.1 YOURCOMPUTER_1.XXX.XXX to your /etc/hosts
I have an app in android in which I created an android client and a Java sever.
But I'm confronting the following issue: my client (the android part) connects to the local machine on port 6000 using the android loopback address.
My server (in Java) listens on local machine at the port 6000 - but what is the IP I have to use to get the socket that accepts the clients?
InetSocketAddress serverAddr = new InetSocketAddress(SERVERIP,serverPort);
serverSocket = new ServerSocket();
serverSocket.bind(serverAddr);
So what is the SERVERIP I have to use?
UPDATE:My client runns on an emulator!!!!!
EDIT:
public class ClientThread implements Runnable {
Object syncToken;
public ClientThread(Object syncToken) {
this.syncToken = syncToken;
}
public void run() {
try {
InetAddress serverAddr = InetAddress.getByName(serverIpAddress);
socket = new Socket(serverAddr, 50458);
} catch (UnknownHostException e) {
System.err.println("Don't know about host");
} catch (IOException e) {
System.err
.println("Couldn't get I/O for the connection to host");
}
try {
out = new PrintStream(socket.getOutputStream());
} catch (IOException e) {
System.out.println(e);
}
while (true) {
synchronized (syncToken) {
try {
syncToken.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
}
And here is: private String serverIpAddress = "10.0.2.2";!!!!!
From http://developer.android.com/guide/developing/devices/emulator.html#emulatornetworking: if you want to communicate from within the emulator to the local host, use IP 127.0.0.1 on the local host and use IP 10.0.2.2 in Android. This should let you communicate between the Android client and the local host server.
You want to run the server part on the Android? I guess not, and in such case using loopback address is not really going to work, as loopback interface on the Android system loops back to the Android machine itself, it is not routed to the outside.
For the serverAddr, use the #InetSocketAddress(int port) constructor, it specifies the wildcard address and a specific port, meaning it listens on all the interfaces of the machine.
Edit: For best results, on the android device use the DNS name of the server to connect to it.