C# 12 in a Nutshell

Chapter 16. Networking

.NET offers a variety of classes in the System.Net.* namespaces for communicating via standard network protocols, such as HTTP and TCP/IP. Here’s a summary of the key components:

• HttpClient for consuming HTTP web APIs and RESTful services

• HttpListener for writing an HTTP server

• SmtpClient for constructing and sending mail messages via SMTP

• Dns for converting between domain names and addresses

• TcpClient, UdpClient, TcpListener, and Socket classes for direct access to the transport and network layers

The .NET types in this chapter are in the System.Net.* and System.IO namespaces.

Note

.NET also provides client-side support for FTP, but only through classes that have been marked as obsolete from .NET 6. If you need to use FTP, your best option is to reach for a NuGet library such as FluentFTP.

Network Architecture

Figure 16-1 illustrates the .NET networking types and the communication layers in which they reside. Most types reside in the transport layer or application layer. The transport layer defines basic protocols for sending and receiving bytes (TCP and UDP); the application layer defines higher-level protocols designed for specific applications such as retrieving web pages (HTTP), sending mail (SMTP), and converting between domain names and IP addresses (DNS).

Figure 16-1. Network architecture

It’s usually most convenient to program at the application ...