The book outlines one of the most promising approaches to professional programming of network applications in C++. The main reasons for the complexity of developing network applications are considered, as well as the design patterns and ACE IIO of the open source intermediate layer, which can be freely loaded from the site to the Internet and which is one of the most portable and widely used C++ network programming tools in the world. The book is addressed to practical developers who need to create flexible and efficient network applications in a short time and without puzzling difficulties.