Java.net.SocketException: Permission denied: connect

Question

I have two PCs in one network that I want to connect. One of them should send a notification to the other via TCP. One the one PC I have a "server" (Python script) socket which waits for the "client"(Jar file) to send a specific String and then it gives me a notification. This works perfectly fine when I'm trying it out one one PC. But when I want to do the intended action the "client" PC's .jar gives me an error that the connection is refused. Do I have to open a specific port on the other PC or what else could cause trouble? One PC runs Fedora the other Windows 8

"Server Code"

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) 
s.bind(("", 5005)) 
s.listen(1)

try: 
    while True: 
        komm, addr = s.accept() 
        while True: 
            data = komm.recv(1024)
            if data == "$":
                noty()
            if not data: 
                komm.close() 
                break
finally: 
    s.close()

"Client" Code

public static void main(String[] args) throws Exception {
Socket socket = new Socket("192.168.178.25", 5005); 
OutputStream out = socket.getOutputStream();
String dat = "$";
    out.write(dat.getBytes());
socket.close();
}

Answer 1

if its permission denied then something is blocking your connection with the computer. i would try to open a port and see if that works. if you want an example of java sockets you can take a look at my SUPER Tic-Tac-Toe Multiplayer it uses java sockets to send strings to the clients as a way to represent what actions the clients should take.

Answer 2

Your server is probably binding to the wrong interface,

calling

s.bind(("", 5005)) 

Without setting an interface will allow the program to pick what ip address / interface it will connect to.

Since your client is trying to connect to ("192.168.178.25", 5005); you may want to put an IP address into the bind call to prevent the server picking the wrong ip interface.

Example:

s.bind(("192.168.178.25", 5005))