Sample TCP/UDP tutorials

Purpose

This code illustrates basic client/server code for TCP and UDP messages in C and Python.

The goal is to illustrate the structure of TCP/UDP applications.

The following is a guide to the Python examples. The C examples are largely similar.

Python TCP Examples

• tcp-1-client.py / tcp-1-server.py -- This is a simple client/server where in the client connects to the server and sends messages (lines of text).
• tcp-2-client.py / tcp-2-server.py -- This extends the prior examples to have the client both send to the server and then receive a reply from the server (the same message). In this example, the server can only interact with a single client.
• tcp-2-client.py / tcp-4-server.py -- This extends the tcp-2-server.py example by having the TCP server be able to accept connections from multiple clients by "forking" the server process.
• tcp-2-client.py / tcp-5-server.py -- This extends the tcp-2-server.py example by having the TCP server be able to accept connections from multiple clients by using the select() system call to check for available data from the clients

Python UDP Examples

• udp-1.py - this program simply accepts a network address and then prints it out using "dotted quad" notation and then as a presentation address.
• udp-2-client.py / udp-2-server.py - The client send a message to the server, which doesn't repond
• udp-3-client.py / udp-3-server.py - The client send a message to the server, and then waits for a response from the server
• udp-4-client.py / udp-3-server.py - The client send a message to the server, and then waits for a response from the server. Unlike the udp-3-client.py example, here the client uses connect() to specify the server address as a property of the socket rather than specifying that address using sendto each time.
• udp-5-client.py / udp-3-server.py - This extends udp-c-client.py to explicit specify the client UDP port using the bind() system call
• udp-6-client.py / udp-3-server.py - This example shows how to use the SO_REUSEADDR socket option to allow multiple sockets to use the same client port address. This can be useful for multi-threaded UDP code.
• udp-7-client.py / udp-3-server.py - This example shows how to use the SO_BROADCAST option to enable broadcast packets
• udp-8-client.py / udp-3-server.py - This example shows how to use the SO_SNDBUF and SO_RCVBUF options to explicitly set the send and receive buffer sizes.