ZyWALL 5/35/70 Series User’s Guide

CH A P T E R 12

Intrusion Detection and

Prevention (IDP)

This chapter introduces some background information on IDP. Skip to the next chapter to see how to configure IDP on your ZyWALL.

12.1 Introduction to IDP

An IDP system can detect malicious or suspicious packets and respond instantaneously. It can detect anomalies based on violations of protocol standards (RFCs – Requests for Comments) or traffic flows and abnormal flows such as port scans.

Figure 110 on page 236 represents a typical business network consisting of a LAN, a DMZ (DeMilitarized Zone) containing the company web, FTP, mail servers etc., a firewall and/or NAT router connected to a broadband modem (M) for Internet access.

Figure 110 Network Intrusions

12.1.1 Firewalls and Intrusions

Firewalls are designed to block clearly suspicious traffic and forward other traffic through. Many exploits take advantage of weaknesses in the protocols that are allowed through the firewall, so that once an inside server has been compromised it can be used as a backdoor to launch attacks on other servers.

Chapter 12 Intrusion Detection and Prevention (IDP)

236