Christian Nagel

Raw Socket Programming

In this chapter, I discuss raw socket programming—I’ll cover the basics of the Internet Control Message Protocol (ICMP) and Simple Network Management Protocol (SNMP). We’ll look at each of these protocols in turn, and build some useful applications to demonstrate the fundamentals of raw socket programming.

Socket Programming in .NET

The preceding chapters talked generally about .NET support for network programming. They showed you how to manipulate streams in .NET applications, and how to use the classes to work with IP addresses and DNS lookups. In this chapter, we’ll start programming with sockets.

Networking Concepts and Protocols

In this chapter, we introduce some of the basic networking concepts and protocols. The chapter serves as a foundation to networking that will allow you to tackle programming in the rest of the book. It doesn’t matter if you plan to develop server applications running as Windows Services (offering some data for clients using a custom protocol), if you write client applications that request data from web servers, or if you create multicasting or mailing applications—you should start with reading this chapter. If you don’t already know what a router or a network switch is, if you aren’t sure about the functionality of the seven layers in the Open Systems Interconnection (OSI) protocol model, or if you just want a refresher or an overview of the different network protocols and their uses, then this chapter is addressed to you.

Network Programming in .NET

In Chapter 1, we presented an overview of networking and looked at the structure and usage of different network protocols such as TCP, UDP, IP, and DNS. In this chapter, we start with network programming using classes from the System.Net namespace.

Cryptography in.NET

Every year computer crime increases dramatically, and it is always a challenge to keep up with the hackers. The System. Security. Cryptography namespace of the.NET Framework provides programmatic access to the variety of cryptographic services that we can incorporate into our applications to encrypt and decrypt data, ensure data integrity, and handle digital signatures and certificates. In this chapter, we’ll explore the System. Security. Cryptography namespace so that we can utilize the cryptographic services in our applications.

E-mail Protocols

Ever since the rise of Internet messaging, e-mail has been a cornerstone of electronic communication. If you’re reading this book, you probably have some prior experience sending e-mail within a programming language, so we aren’t really covering some new and exciting technology that.NET brings to the table. What is exciting is how easy and seamless.NET makes network programming, especially with regard to using the various e-mail protocols to send and retrieve e-mail, and to perform various tasks that may have been convoluted or difficult in the past.

Streams in .NET

A stream is an abstract representation of a sequence of bytes such as a file, an I/O device, or a TCP/IP socket. Through this abstraction, different devices can be accessed with the same process, and similar code can be used to read data from a file input stream, as can be used to read data from a network input stream, for example. Furthermore, the programmer’s need to worry about the actual physical mechanism of the device is removed.