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

Chapter 1, Introducing Networks and Protocols

  1. What are the key differences between IPv4 and IPv6?

IPv4 only supports 4 billion unique addresses, and because they were allocated inefficiently, we are now running out. IPv6 supports 3.4 x 1038 possible addresses. IPv6 provides many other improvements, but this is the one that affects our network programming directly.

  1. Are the IP addresses given by the ipconfig and ifconfig commands the same IP addresses that a remote web server sees if you connect to it?

Sometimes, these addresses will match, but not always. If you're on a private IPv4 network, then your router likely performs network address translation. The remote web server then sees the translated address.If you have a publicly routable IPv4 or IPv6 address, then the address seen by the remote web server will match those reported by ipconfig and ifconfig.

  1. What is the IPv4 loopback address?

The IPv4 loopback address is, and it allows networked programs to communicate with each other while executing on the same machine.

  1. What is the IPv6 loopback address?

The IPv6 loopback address is ::1. It works in the same way as the IPv4 loopback address.

  1. How are domain names (for example, resolved into IP addresses?

DNS is used to resolve domain names into IP addresses. This protocol is covered in detail in Chapter 5Hostname Resolution and DNS.

  1. How can you find your public IP address?

The easiest way is to visit a website that reports it for you.

  1. How does an operating system know which application is responsible for an incoming packet?

Each IP packet has a local address, remote address, local port number, remote port number, and protocol type. These five attributes are memorized by the operating system to determine which application should handle any given incoming packet.