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

Spam-blocking pitfalls

It can be much harder to send emails today than it was in the past. Spam has become a major problem, and every provider is taking actions to curb it. Unfortunately, many of these actions can also make it much more difficult to send legitimate emails.

Many residential ISPs don't allow outgoing connections on port 25. If your residential provider blocks port 25, then you won't be able to establish an SMTP connection. In this case, you may consider renting a virtual private server to run this chapter's code.

Even if your ISP does allow outgoing connections on port 25, many SMTP servers won't accept mail from a residential IP address. Of the servers that do, many will send those emails straight into a spam folder.

For example, if you attempt to deliver an email to Gmail, you may get a response similar to the following:

550-5.7.1 [] The IP you're using to send mail is not authorized
550-5.7.1 to send email directly to our servers. Please use the SMTP
550-5.7.1 relay...