Before starting this book, you should be familiar with computers and networks from the point of view of a user. This should include knowledge of the home setup, as well as computer networks in a commercial setting. Familiarity with the technologies used to administer and maintain a network, particularly Cisco products, is helpful, but not essential. Knowing that switches, routers, and servers exist – and how they differ – is a requirement.

This book follows on from the 210-250 (SECFND) syllabus, so support materials for those courses may be a useful start, and could be used as reference material if you feel that you are struggling with any of the topics found here. You will have to pass both the 210-250 and 210-255 certification exams for CCNA Cybersecurity Operations anyway, so the 210-250 certification book is a good investment regardless.

To get the most out of the course, you should try to engage with the teaching methods used. The content is broadly separated into three 3 elements – theory, formative questions (with reasoned answers), and testing questions. The theory sections contain a distilled version of the knowledge required – there is a direct correlation between the theory sections and the syllabus. Formative questions are included at the end of each chapter, and are designed to test your ability to recall information from the chapter, analyze a scenario, and apply the theory in practice. The back of the book includes the answers and, most importantly, the rationale. Finally, there are two mock exam papers. These will test your ability to apply the theory in practice, and to help prepare you for the certification exam. The answers, but not the rationale, are provided for these questions. If you are making mistakes, a good activity would be to try to reanalyze the question with the correct answer, and see whether you can generate the rationale retrospectively.

There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "The only method of differentiation is that the legitimate csrss.exe process is run from the C:\Windows\System32 folder."

Any command-line input or output is written as follows:

$ tcpdump -ns 0 -eX -r dns.pcap

Bold: Indicates a new term, an important word, or words that you see on screen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "Select System info from the Administration panel."