How to use STunnel for TCP Server/Client where Client sends out on port 39000

I have a TCP Server/Client where the Server listens on port 5000 and the Client outgoing port is 39000.

I have Stunnel set up on the Server:

[custom]
accept  = 6000
connect = 5000

... so it accepts connections on port 6000 and redirects it to 5000 (which my Server.c is listening on).

I tried to set up STunnel on the Client in the following way:

[custom_cl]
accept = 39000
connect = 192.168.1.3:6000

...so it accepts any data from port 39000 and sends it to the Server (let's say it's at 192.168.1.3) at port 6000.

My client has this code:

client_addr.sin_family = AF_INET;
client_addr.sin_port = htons(39000);
client_addr.sin_addr.s_addr = inet_addr("0.0.0.0");
bzero(&(client_addr.sin_zero),8);

if (bind(sock, (struct sockaddr *)&client_addr, sizeof(struct sockaddr))
                                                               == -1) {
     perror("Unable to bind");
     exit(1);
     }

...so that it will always send out on port 39000. My problem is that I re开发者_JAVA技巧ceive an "Unable to bind: Address already in use" because (I'm guessing) STunnel is listening on port 39000. What should I be doing?

You don't need to bind a socket for outgoing connection (unless you know what you are doing and what for). You just need to create a socket and call connect(). You pass localhost (or 127.0.0.1) as destination address and 39000 as destination port.

In your code snippet you are binding the client side of the connection to port 39000. Don't do that. Just issue the connect(2) as @Eugine writes in his answer.