ZyXEL Communications ZYWALL P1 User Manual page 14

Table of Contents
9.1 Firewall Overview ............................................................................................................. 141
9.2 Packet Direction Matrix ...................................................................................................... 142
9.3 Packet Direction Examples ................................................................................................ 143
9.3.1 To VPN Packet Direction .......................................................................................... 144
9.3.2 From VPN Packet Direction ..................................................................................... 145
9.3.3 From VPN To VPN Packet Direction ........................................................................ 146
9.4 Security Considerations ..................................................................................................... 147
9.5 Firewall Rules Example ..................................................................................................... 148
9.6 Asymmetrical Routes ......................................................................................................... 150
9.6.1 Asymmetrical Routes and IP Alias ........................................................................... 150
9.7 Firewall Default Rule (Router Mode) ................................................................................. 150
9.8 Firewall Default Rule (Bridge Mode) ................................................................................ 152
9.9 Firewall Rule Summary .................................................................................................... 154
9.9.1 Firewall Edit Rule
9.10 Anti-Probing
9.11 Firewall Thresholds
9.11.1 Threshold Values .................................................................................................... 161
9.12 Threshold Screen ............................................................................................................ 161
9.13 Service ............................................................................................................................ 163
9.13.1 Firewall Edit Custom Service ................................................................................ 165
9.14 My Service Firewall Rule Example .................................................................................. 166
Chapter 10
Intrusion Detection and Prevention (IDP)........................................................................... 171
10.1 Introduction to IDP
10.2 Firewalls and Intrusions ................................................................................................... 171
10.3 IDS and IDP .................................................................................................................... 172
10.4 Host IDP ......................................................................................................................... 172
10.5 Network IDP ................................................................................................................... 172
10.6 Example Intrusions .......................................................................................................... 172
10.6.1 SQL Slammer Worm .............................................................................................. 173
10.6.2 Blaster W32.Worm ................................................................................................. 173
10.6.3 Nimda ..................................................................................................................... 173
10.6.4 MyDoom ................................................................................................................. 173
10.7 ZyWALL IDP .................................................................................................................... 174
Chapter 11
Configuring IDP..................................................................................................................... 175
11.1 Overview .......................................................................................................................... 175
11.2 General Setup .................................................................................................................. 175
11.3 IDP Signatures ................................................................................................................. 177
11.3.1 Attack Types ........................................................................................................... 177
11.3.2 Intrusion Severity .................................................................................................... 178
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ZyWALL P1 User's Guide