Tcl (Tool Command Language) is a very powerful and easy to learn dynamic programming language, suitable for a very wide range of uses. Tcl is regarded as one of the best-kept secrets in the software industry. This book gives you a hands-on experience on Tcl, helping you develop network-aware applications using this mature yet evolving language. This book shows you how to create network-aware applications with Tcl language. Packed with practical examples, the book not only takes you through the implementation of network protocols in Tcl, but also key aspects of Tcl programming. The book starts with the basic element of Tcl programming as we take a look at the syntax and fundamental commands of the language. To get us ready for network programming, we look at important Tcl features such as object-oriented programming, accessing files, packaging in TCL, event driven programming, and multithreaded applications. To create standalone single-file executable applications with Tcl we take a look at the Starpack technology, and ensure that we ll be able to create robust applications with a thorough coverage of troubleshooting and debugging Tcl applications. The book is really about network programming, and it will not let you down with its deep coverage of these topics. Of course we look at protocols, but there are plenty of practical examples to keep things moving along. We start with the TCP and UDP protocols, and look at some other protocols to see examples of synchronizing time with other servers, querying user information and authenticating users over LDAP and performing DNS queries. The book explains Simple Network Management Protocol (SNMP), which is often used for monitoring and gathering information from various devices, such as routers, gateways, printers and many other types of equipment. We ll also look at web programming in Tcl; processing the requests coming from the clients via the HTTP protocol and responding to these requests. You ll be able to create a complete solution for creating a client-server application in Tcl. To round things off, you ll see how to secure your networked applications, build public key infrastructure into your application and use Tcl s safe interpreter feature to reduce risk of running code from unknown source. This book will be help you discover a range of network protocols and concepts and show how to implement them in Tcl.