Book Image

Implementing and Administering Cisco Solutions: 200-301 CCNA Exam Guide

By : Glen D. Singh
Book Image

Implementing and Administering Cisco Solutions: 200-301 CCNA Exam Guide

By: Glen D. Singh

Overview of this book

In the dynamic technology landscape, staying on top of the latest technology trends is a must, especially if you want to build a career in network administration. Achieving CCNA 200-301 certification will validate your knowledge of networking concepts, and this book will help you to do just that. This exam guide focuses on the fundamentals to help you gain a high-level understanding of networking, security, IP connectivity, IP services, programmability, and automation. Starting with the functions of various networking components, you’ll discover how they are used to build and improve an enterprise network. You’ll then delve into configuring networking devices using a command-line interface (CLI) to provide network access, services, security, connectivity, and management. The book covers important aspects of network engineering using a variety of hands-on labs and real-world scenarios that will help you gain essential practical skills. As you make progress, this CCNA certification study guide will help you get to grips with the solutions and technologies that you need to implement and administer a broad range of modern networks and IT infrastructures. By the end of this book, you’ll have gained the confidence to pass the Cisco CCNA 200-301 exam on the first attempt and be well-versed in a variety of network administration and security engineering solutions.
Table of Contents (26 chapters)
1
Section 1: Network Fundamentals
6
Section 2: Network Access
9
Section 3: IP Connectivity
12
Section 4: IP Services
15
Section 5: Security Fundamentals
20
Section 6: Automation and Programmability
22
Chapter 16: Mock Exam 1
23
Chapter 17: Mock Exam 2

ACL operation

ACLs are rules created by a network professional on the router or firewall appliance to filter traffic either entering or leaving the device. ACLs are a list of security rules, with each ACL containing either a permit or deny statement. Each statement within an ACL is referred to as an Access Control Entry (ACE). These ACEs are the real workers that allow and block packets between networks. When a router receives packets on an interface, the router checks each ACE, starting with the first entry at the top of the list and moving down until a match is found. Once a matching ACE is found, the router stops searching and executes the rule on the ACE, either permitting or denying the traffic. This process is known as packet filtering.

Important note

If no matches are found in the ACLs, the packet is discarded by the router. The last ACE within all ACLs is an implicit deny statement. An implicit deny statement simply states that if no matches are found in the previous...