Networking is one of the core tasks of enterprise-level programming, and for the programmer familiar with the C# language this book should provide the information to put network programming at the heart of their .NET applications. Prior knowledge of network programming is not assumed, but the reader already familiar with networking from another environment will find the pace quick enough for the book to still prove valuable. This book should give the reader: an understanding of the general concepts of networking; information about network programming in .NET with C#; skills to build network-based applications in .NET; and the confidence to use the classes shipped with .NET to implement your own application-level protocols.The book begins with an overview of the most important background material, such as the architecture of physical networks, network protocols, the OSI model, streams in .NET, and the classes provided to facilitate access to streams such as StreamReader and StreamWriter. Then it moves onto sockets programming, with an introduction to the concept of sockets, and full coverage of using sockets in .NET. It looks at TCP, UDP, and using multicast sockets in .N ET and at application-level protocols built on top of these layers, such as SMTP and FTP. The next stop is Internet programming, with a look at HTTP, the underlying protocol of the Internet, and e-mail protocols. The book finishes with an exploration of how to secure network communications in .NET - encrypting network traffic, certificates and SSL, authenticating and authorizing users with NTLM and Kerberos.Assumes knowledge of: .NET Framework, C#, Networking, IP, TCP, UDP, HTTP, FTP, POP3, IMAP, SMTP, NNTP