Server Socket only accept from certain IP addresses?

Question

I'm trying to write a Server Socket that listens for connections. But I only want it to accept connections from known IP addresses. If I'm using the code below:
try {
serverSocket = new ServerSocket(myPort);
} catch (IOException e) {
for (;;) { //loop forever
Socket clientSocket = null;
try {
clientSocket = serverSocket.accept();
Is there a way that I can influence the serverSocket.accept() method to make it first check the IP address BEFORE the connection is made? If not, then is it a security vulnerability to do the following code (knownClientAddress is the only IP address I want to accept connections from):
try {
serverSocket = new ServerSocket(myPort);
} catch (IOException e) {
for (;;) { //loop forever
Socket clientSocket = null;
try {
clientSocket = serverSocket.accept();
if (clientSocket.getRemoteSocketAddress() != knownClientAddress)
clientSocket.close();
}

Answer 1

jobocop17 wrote:
what would such an interface look like / example? Would that be sufficient for socket security? Can you spoof the IP when using such a method?He doesn't mean interface in the java type hierarchy sense. He means network interface. Like if your machine is on a LAN, with a 10.0, or 192.168 address AND has a public IP address as well. The IP address can be spoofed no matter where it comes from, but if you're only accepting connections on the NIC that's on your LAN, not from one that's on the WAN, then you may be able to trust all the potential connectors, and not have to worry about filtering the incoming address. The outward facing router should take care of the rest for you, or at the very least, will be better equipped to do so than any code that you could write.