Book Image

Hands-On Network Programming with C# and .NET Core

By : Sean Burns
Book Image

Hands-On Network Programming with C# and .NET Core

By: Sean Burns

Overview of this book

The C# language and the .NET Core application framework provide the tools and patterns required to make the discipline of network programming as intuitive and enjoyable as any other aspect of C# programming. With the help of this book, you will discover how the C# language and the .NET Core framework make this possible. The book begins by introducing the core concepts of network programming, and what distinguishes this field of programming from other disciplines. After this, you will gain insights into concepts such as transport protocols, sockets and ports, and remote data streams, which will provide you with a holistic understanding of how network software fits into larger distributed systems. The book will also explore the intricacies of how network software is implemented in a more explicit context, by covering sockets, connection strategies such as Transmission Control Protocol (TCP) and User Datagram Protocol (UDP), asynchronous processing, and threads. You will then be able to work through code examples for TCP servers, web APIs served over HTTP, and a Secure Shell (SSH) client. By the end of this book, you will have a good understanding of the Open Systems Interconnection (OSI) network stack, the various communication protocols for that stack, and the skills that are essential to implement those protocols using the C# programming language and the .NET Core framework.
Table of Contents (26 chapters)
Free Chapter
Section 1: Foundations of Network Architecture
Section 2: Communicating Over Networks
Section 3: Application Protocols and Connection Handling
Section 4: Security, Stability, and Scalability
Section 5: Advanced Subjects

The DNS in C#

It is occasionally necessary to identify the underlying IP address for a domain name from within the context of our software. For that, .NET Core provides the static Dns class as part of the System.Net namespace. With the Dns class, we can access directory information as returned by the nearest downstream name server capable of resolving the given name. We can request an instance of the IPHostEntry class, containing all of the relevant directory information of a DNS entry, or simply an array of IP addresses registered to resolve requests against the domain name.

To see this in action, simply invoke any of the methods exposed by the static Dns class in a sample program as follows:

using System;
using System.Net;
using System.Threading;

namespace DnsTest {
public class DnsTestProgram {
static void Main(string[] args) {
var domainEntry = Dns.GetHostEntry...