Android connect to tethering socket

Question

I have 2 android devices, one acts as a server that is in tethering mode, and accepting connections to a port. The other device acts as a client that connects to the server hotspot and establishes a connection to the server via a port. (Everything is done without a router in the middle).

The server code looks like this: (When the android server executes the code, the device is in tethering mode)

ServerSocket server = new ServerSocket(PORT);  while (true) {     Socket client;     client = server.accept();     ClientThread com = new ClientThread(client, this);     Thread t = new Thread(com);     t.start(); } 

The client code looks like this: (when the android client executes this code, the device is connected to access point)

Socket client = new Socket(); int serverIP = wifiManager.getDhcpInfo().serverAddress; String stringIP = android.text.format.Formatter.formatIpAddress(serverIP); InetAddress address = InetAddress.getByName(stringIP); SocketAddress socketAddress = new InetSocketAddress(address, PORT); client.connect(socketAddress); 

I get the following error on the client

java.net.ConnectException: failed to connect to /192.168.43.1 (port 12345): connect failed: ENETUNREACH (Network is unreachable)   at libcore.io.IoBridge.connect(IoBridge.java:114)   at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)   at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459)   at java.net.Socket.connect(Socket.java:842)   at java.net.Socket.connect(Socket.java:785)   at com.alternatewifimeshmessaging.HostManager.clientConnect(HostManager.java:283)   at com.alternatewifimeshmessaging.HostManager.client(HostManager.java:189)   at com.alternatewifimeshmessaging.HostManager.run(HostManager.java:59)   at java.lang.Thread.run(Thread.java:856) Caused by: libcore.io.ErrnoException: connect failed: ENETUNREACH (Network is unreachable)   at libcore.io.Posix.connect(Native Method)   at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:85)   at libcore.io.IoBridge.connectErrno(IoBridge.java:127)   at libcore.io.IoBridge.connect(IoBridge.java:112) ... 8 more 

The server gives no errors.

I have the following permission set in the android manifest file:

<uses-permission android:name="android.permission.INTERNET" > </uses-permission> <uses-permission android:name="android.permission.CHANGE_WIFI_STATE" > </uses-permission> <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" > </uses-permission> 

Ideally I would need to transfer some data from server to the client.

What am I doing wrong?

Answer 1

By testing it turns out the connection cannot be established on the tethering device.

But if we reverse the process and open a serversocket on the connected client. And connect to it from the tethering device, it will work.

So reversing the communication is the answer.