I have two interfaces in a solaris host. I would like to initiate two TCP connections to a single TCP server via both interfaces as shown in the diagram. Are there any options in Java to bind the interface to the TCP socket to override the local routing table?
I am attaching the network diagram,
I would like to use both the serial links bandwidth to get the data from server. Hence I would like to initiate the connection on both the interfaces.
thanks,
You can use
Socket s = new Socket(hostname, port, localInterface, 0);
However, many OSes do not honour this "hint" and will use the routing table anyway.
Do you mean something like this:
Socket socket1 = new Socket();
socket1.bind(new InetSocketAddress("10.1.1.1", port));
socket1.connect(new InetSocketAddress("10.1.3.1", port));
Socket socket2 = new Socket();
socket2.bind(new InetSocketAddress("10.1.2.1", port));
socket2.connect(new InetSocketAddress("10.1.3.1", port);
Related
I am doing a project for which connection between server and client is required.
I did it by adding TCP sockets.
Here is the code fraction :
Server:
ServerSocket welcomeSocket = new ServerSocket(80);
while(true)
{
Socket connectionSocket = welcomeSocket.accept();
WorkerThread wt = new WorkerThread(connectionSocket, id);
Thread t = new Thread(wt);
t.start();
workerThreadCount++;
}
Client :
Socket skt = new Socket("192.168.0.108", 80); // The IP address is from cmd->ipconfig/all-> IPv4 Address
outToServer = new PrintWriter(skt.getOutputStream(), true);
inFromServer = new BufferedReader(new InputStreamReader(skt.getInputStream()));
It all works when both ends are in same device/under same WiFi.But I don't understand what to do for creating connection over internet.
Please help with clear steps.
Here:
Socket skt = new Socket("192.168.0.108", 80);
That is local address. If you want to have a server that is reachable on the internet, then that server needs to have its global public IP address!
In other words: you have to make sure that the server can be reached from the internet somehow. For example by turning to some service provider that hosts servers that you can then equip with your code!
The whole purpose of 192.168 addresses is to be defined only in a local subnet.
Alternatively, you have to check if your ISP has a service where the ISP assigns an IP address to your connection, and that allows calls from the internet to go to your "place".
Meaning: when you want to receive phone calls, you need a phone that is connected to the phone net!
In order to connect to a socket over WAN, you must port forward that port to your local device. This can be done in your routers' settings.
192.168.0.108 --> That's your local IP-address.
This can be used on your local network without any requirements for port forwarding whatsoever. However, to use it over WAN, execute the following steps:
Step 1: Search for your routers' model number and port forwarding on Google on how-to forward port 80 to your local IP-address. Warning: use a static IP-address on your local device to prevent your IP from changing after a reboot.
Step 2: Go to a website like IP Chicken and find your external IP-address.
You can then connect to your socket using:
Socket skt = new Socket("[EXTERNALIP]", 80);
Please be noticed: unless you have a business network, your external IP-address will probably change from time to time.
I'm using multicast to implement a simple discovery service. Several instances on the application must be able to run on the same host, I therefore end up with several multicast sockets that are members of the same group on the same host.
On Linux, this works as expected. Every instance of the application on a host receives the messages sent to the multicast address.
On Windows however, only the first application to join the multicast group receives the messages sent.
Here is the code I'm using to create my multicast socket:
socket = new MulticastSocket(PORT);
InetAddress group = InetAddress.getByName(ADDRESS);
socket.joinGroup(group);
socket.setTimeToLive(TTL);
Is there some option I need to set? I've tried scouring the API but I can't find anything.
EDIT: According to this website, I need to set SO_REUSEADDR, but this can only be set before the socket binds. It seems the constructor for MulticastSocket seems to bind the socket upon creation.
you do this by creating the socket with no arguments and then call bind on that object.
socket = new MulticastSocket();
socket.setReuseAddress(true);//redundant, already set with empty constructor
SocketAddress sockAddr = new InetSocketAddress(PORT);
socket.bind(sockAddr);
InetAddress group = InetAddress.getByName(ADDRESS);
socket.joinGroup(group);
socket.setTimeToLive(TTL);
I would like to read the messages from a particular port.For example the IP is 1.2.3.4 and the port is 1000. Already the IP is used for receiving some messages. What I would like to do is to listen to that particular IP and receive all the messages using a java program. Will
SocketServer do the purpose??
ServerSocket ss = new ServerSocket(1000);
Socket socket = new Socket("1.2.3.4",1000);
socket = ss.accept();
Is it possible to read every contents that are being received by the particular IP and port?
To listen to a specific address you have to create a ServerSocket like this
ServerSocket ss = new ServerSocket(); // Unbound socket
ss.bind(new InetSocketAddress("1.2.3.4", 1000)); // Bind the socket to a specific interface
Socket client = ss.accept();
This way the server socket is bound to a specific network interface and will only receive incoming connections from it.
I have a Server Socket and 3-4 android devices as clients. I'm using TCP/IP for communications. Which is the best method. Should I use multiple ports for each client? Or should I use same port. If using same function then how should I identify the communication addressed to different devices?
No, you do not need several ports.
ServerSocket server = new ServerSocket(port);
while (true)
{
Socket socket = server.accept();
// do something with this socket - aka 1 client
new SomeClientClass(socket);
InputStream in = socket.getInputStream();
in.read(byte[]);
OutputStream out = socket.getOutputStream;
// out will only write response to its own client.
// when this new SomeClientClassis created, method returns to this point
// in while loop and waits for the next client
}
You can use one port. The client can send you its id. If it can't you can look at the clients IP address to workout which one it is.
There are thousands of TCP client/server code examples on the web, but I would start with the sample code which comes with the JDK,
I am creating a socket for TCP communication and would like to know how to specify a source port.
Socket socket = new Socket();
socket.connect(dstAddress);
After creating your new socket, call bind() with the local port number you want to use, then connect to the remote host.
#EJP is correct, though. Don't do this lightly since you can end up not being able to create the socket if something else happens to be using that port or even if your program has recently used it and closed it.
If it's not working, you may need to look at the library you're using.
Socket has multiple constructors. Try this one
You have to use InetSocketAddress, declared in the package java.net. The easiest way to use it is:
InetSocketAddress(host, port)), something like this:
Socket socket = new Socket();
socket.connect(new InetSocketAddress("http://myserver.com", 80));
Which connect to the web server listening on the port 80 in myserver.com.