ZyXEL Communications 70 Series User Manual

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ZyWALL 5/35/70 Series User’s Guide
Chapter 12 Intrusion Detection and Prevention (IDP)
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 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.
 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.