Network Programming
Language: C

Task 1 Unix Domain Protocol – Connectionless

1. Modify both Unix Domain Protocol – Connectionless server and client program so that the server sends the received message back to the client.
   
   

Task 2 Unicast and Multicast programs

1. You are required to modify three (3) programs as follows:
   a. unicast_client.c: (refer to Lab 1 udp_client.c)
   i. This program will send a unicast message to the server.
   ii. It will repeatedly request user input until the user types “Good bye”.
   b. multicast_sender.c: (refer to Lab 4 multicast_sender.c)
   i. This program will receive a unicast message from the unicast client.
   ii. It will then forward the received message to the multicast receiver(s) who joined the multicast group.
   c. multicast_receiver.c: (refer to Lab 4 multicast_receiver.c)
   i. This program will receive a multicast message from the server if it has correctly joined the designated multicast group.
   ii. This program will NOT receive a multicast message from the server if it has joined the incorrect multicast group.
   
2. The unicast IP address, unicast port number, multicast IP address, and multicast port number are specified when the program is executed in the terminal.
   -E.g., ./m_s 224.0.0.15 192.168.56.101 5000
   -Multicast IP address: 224.0.0.15
   -Multicast Port Number: 5000
   -Unicast IP address: 192.168.56.101
   -Unicast Port Number: 4999 (multicast port number – 1)
   
3. To verify if your programs are running correctly, below are the steps.
   a. Start one (1) server in a new terminal by using the following commands:
   ./m_s 224.0.0.15 192.168.56.101 5000
   b. Start one (1) sender in a new terminal by using the following commands:
   ./u_c
   c. Open three (3) separate terminals and start three (3) receivers using following commands:
   ./m_r 224.0.0.15 192.168.56.101 5000
   ./m_r 224.0.0.15 192.168.56.101 5000
   ./m_r 224.0.0.25 192.168.56.101 4998