port forward problem

EyeSight

Hi, simple question regarding port forwarding. i have a simple java server i want accessible from the entire internet, so i'm trying to forward port 4242 to my laptops ip address. however my cisco router is telling me it's an invalid ip address when i try to port forward.
has anybody any idea on what i'm doing wrong? i don't understand NATs too much and i'm almost certain this isn't a firewall problem

try{
            //makes a socket listening on port 4242
            ServerSocket serverSocket = new ServerSocket(4242);
        
            while(true){
                Socket socket = serverSocket.accept();
                InputStreamReader streamReader = new InputStreamReader(socket.getInputStream());
                BufferedReader reader = new BufferedReader(streamReader);
                
                String input = reader.readLine();
                System.out.println(input);                
            }    
        }
        catch(Exception ex){
            ex.printStackTrace();
        }

DublinDilbert

How is your laptop getting its IP on the local network? is it via DHCP or Static? You should set up your laptop to have a static IP address locally then forward the required ports onto this address. The static IP address you assign to your laptop should be outside the range of dynamic IPs that the router assigns.

EyeSight

DublinDilbert wrote: »

How is your laptop getting its IP on the local network? is it via DHCP or Static? You should set up your laptop to have a static IP address locally then forward the required ports onto this address. The static IP address you assign to your laptop should be outside the range of dynamic IPs that the router assigns.

Thanks for the reply

I have given my laptop a static ip: 192.168.1.100
And i have forwarded the port like so:
Local IP Adr: 192.168.1.100
Start Port : 4242
End Port: 4242
Protocol: both


in my client i connect via the ip address of the router to port 4242 however it still does not connect. any idea on what i'm missing?

Baz_

Can you connect from another computer within the lan? Is the server definitely working?

EyeSight

sorry! i restarted everything and it seems to work now.

thanks a lot!