Network Security

What this chapter covers

Network Security is the most hands-on chapter of the exam, because it is about configuring and troubleshooting devices.

It covers how firewalls and intrusion prevention are deployed, how to watch the network, and how to harden switches and routers. It also covers AAA, secure management protocols, and policy and VPN work on Cisco Secure Firewall Threat Defense (FTD).

The pages follow the ten topics that the question bank uses for this chapter, and each page shows commands for the right platform.

How the topics fit together

Think of the chapter as a path from the edge of the network, to the devices inside it, to the people who manage them.

The first page compares deployment models and the telemetry that makes monitoring possible. The next two pages harden the access layer, with segmentation and port security and then DHCP snooping, ARP inspection and storm control.

The middle of the chapter is about control of the devices themselves. It covers management options and CIS benchmarks, AAA troubleshooting, and secure management protocols such as SNMPv3, NETCONF, RESTCONF, syslog and NTP.

The last two pages apply what you learned to the firewall. They cover FTD access control and threat inspection, and then FTD VPN setup and troubleshooting.

How to use these pages

Each topic page has the same shape, so you can skim for what you need.

• What it is: the idea in plain words.
• How it works: the mechanism, with diagrams and example commands.
• What to remember for the exam: the facts to memorise.
• Common mistakes: the classic traps.
• Check yourself: three questions to test your understanding.

Practise the switch and router commands in a simulator, because typing them builds recall. For FTD and FMC, which are graphical, learn the order of the steps and the purpose of each setting.