Client–Server Network (Custom UDP DNS)

This project is a custom DNS client–server system built in C# (.NET) using UDP sockets.
This assignment was made for my Networking class, which focuses on implementing a simplified DNS protocol using raw socket communication.

The application consists of two console programs:

• Client → Sends DNS lookup requests
• Server → Receives, processes, and responds to those lookups

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How It Works

The client and server communicate via UDP using Socket.SendTo() and Socket.ReceiveFrom().

Each message is formatted as a JSON object that includes a message ID, type, and content.

The communication flow:

1. Handshake – The client sends a “Hello” message and receives a “Welcome” from the server.
2. DNS Lookup – The client sends lookup requests containing a record type and domain name.
3. Reply / Error – The server checks the data source (a JSON-based DNS list) and sends either:
   • A valid record (DNSLookupReply)
   • Or an error message (Error)
4. Acknowledgment – The client confirms each reply with an Ack message.
5. End – Once all requests are complete, the server sends an End message to close communication.

The server stays active after completion, waiting for the next client.