(?? This book focuses on ciscoip access tables, mainly about the operation and use of access tables, and provides more than 100 examples, so that readers can refer to this book to meet their own special operation needs.?? Access table is the first step in network defense against external attacks. In addition, the access table is also a mechanism to control the flow of information through the router interface. In this way, readers can use access tables to design network operations and control network data flow. Conversely, by using the access table of the router, readers can also establish specific network planning strategies.?? This book is one of Cisco's professional technology series, which follows the method of introducing relevant knowledge first, and then giving specific examples of application. We will review different types of access tables, and then introduce their formats, keyword usage, creation methods, and how to apply them to interfaces. In addition, each chapter focuses on a specific access table, and gives a large number of standard application examples. This form of organization first outlines the network applications or requirements, then realizes the network applications or requirements with the help of access tables, network scheme diagrams and necessary ciscointernetonlineservice (IOS) statements, and finally provides application examples of IOS statements. The author tries to provide readers with some examples in real life, so that readers can easily transform them to meet specific needs.?? As a professional writer, we expect readers to give feedback. If readers are willing to share their views on the fields covered in this book with us, or what topics they want to know in the future version of this book, or if they want the author to introduce other topics related to Cisco in a more professional field, readers can contact us through the publisher, or contact us directly through email.?? GilbertHeld?? Macon,Georgia?? gil_ held@yahooKentHundley ?? Stanford,Kentucky?? kent. hundley@prodigy)