Book Image

Hands-On Network Programming with C

By : Lewis Van Winkle
Book Image

Hands-On Network Programming with C

By: Lewis Van Winkle

Overview of this book

Network programming enables processes to communicate with each other over a computer network, but it is a complex task that requires programming with multiple libraries and protocols. With its support for third-party libraries and structured documentation, C is an ideal language to write network programs. Complete with step-by-step explanations of essential concepts and practical examples, this C network programming book begins with the fundamentals of Internet Protocol, TCP, and UDP. You’ll explore client-server and peer-to-peer models for information sharing and connectivity with remote computers. The book will also cover HTTP and HTTPS for communicating between your browser and website, and delve into hostname resolution with DNS, which is crucial to the functioning of the modern web. As you advance, you’ll gain insights into asynchronous socket programming and streams, and explore debugging and error handling. Finally, you’ll study network monitoring and implement security best practices. By the end of this book, you’ll have experience of working with client-server applications and be able to implement new network programs in C. The code in this book is compatible with the older C99 version as well as the latest C18 and C++17 standards. You’ll work with robust, reliable, and secure code that is portable across operating systems, including Winsock sockets for Windows and POSIX sockets for Linux and macOS.
Table of Contents (26 chapters)
Title Page
About Packt


This chapter was all about hostnames and DNS queries. We covered how the DNS works, and we learned that resolving a hostname can involve many UDP packets being sent over the network.

We looked at getaddrinfo() in more depth and showed why it is usually the preferred way to do a hostname lookup. We also looked at its sister function, getnameinfo(), which is capable of converting an address to text or even doing a reverse DNS query.

Finally, we implemented a program that sent DNS queries from scratch. This program was a good learning experience to better understand the DNS protocol, and it gave us a chance to gain experience in implementing a binary protocol. When implementing a binary protocol, we had to pay special attention to byte order. For the simple DNS message format, this was achieved by carefully interpreting bytes one at a time.

Now that we've worked with a binary protocol, DNS, we will move on to text-based protocols in the next few chapters. In the next chapter, we will learn...