Network Sockets (ITS8020)
The goal is to try sending and receiving data over the socket interface
You will use socket(), connect(), bind(), listen(), accept() and socket addresses for the task.
There are two separate tasks.
Write a program which tries connecting to a specified machine on specified port so the following command:
connect www.lambda.ee 80
would connect to www.lambda.ee on port 80. Write
GET / HTTP/1.0\r\n\r\n
to the socket and display any resulting data on screen. Terminate when connection is closed.
Write a server program which shows on screen whatever data is received from the network. The command line:
would listen on port 3333 and display any received connections.
When connection is made, display the address of the other connection, then display the data until connection is closed.
If the former part of the exercises does not provide you with sufficient brain-stimulation. Please try the following: Create a program which outputs the output of "ls -l" to the network on the given socket when connected; using dup() or dup2() functions. For running a progam you could use fork() and execv(). It could work as follows:
And then you could try it out using netcat for example.
Use netcat for connecting and listening to your program:
nc www.lambda.ee 80 nc -l 8080
Note that you can only listen to ports starting from 1024. In addition to that, the Dijkstra server has an external firewall which prevents connections from outside unless you listen on ports 7400-8000 .