TCP Client and server


I have STM32F429ZI nucleo board and I’m trying to use the board as a client and my laptop is the server. I tried the example in the mbed handbook:

I’m facing an issue to establish the communication between my laptop and the board. Both are on the same Network. I used the ipconfig in the cmd to know the IP of my laptop but I think the problem with the port. I wrote netstat -a in the cmd and there is a lot of port numbers and I choose more than one but it didn’t work. the client will reply:

unable to connect to the ip address of the server with the port number.

Which port should I choose to be able to connect?

Thank you