Table of Contents
P-2802H(W)(L)-I Series User’s Guide
15
10.16 PSTN Line Screen
(“L” models only)
............................................................................
152
Chapter
11
Firewalls
.................................................................................................................................
155
11.1 Firewall Overview
.............................................................................................................
155
11.1.1 Stateful Inspection Firewall
.....................................................................................
155
11.1.2 About the ZyXEL Device Firewall
...........................................................................
155
11.1.3 Guidelines For Enhancing Security With Your Firewall
..........................................
156
11.2 General Firewall Policy Overview
...................................................................................
156
11.3 Security Considerations
...................................................................................................
158
11.4 Triangle Route
.................................................................................................................
158
11.4.1 The “Triangle Route” Problem
................................................................................
158
11.4.2 Solving the “Triangle Route” Problem
....................................................................
159
11.5 General Firewall Policy
...................................................................................................
160
11.6 Firewall Rules Summary
.................................................................................................
161
11.6.1 Configuring Firewall Rules
...................................................................................
163
11.6.2 Customized Services
.............................................................................................
166
11.6.3 Configuring A Customized Service
.......................................................................
166
11.7 Example Firewall Rule
.....................................................................................................
167
11.8 Firewall Thresholds
.........................................................................................................
171
11.8.1 Threshold Values
....................................................................................................
172
11.8.2 Configuring Firewall Thresholds
.............................................................................
172
Chapter
12
Content Filtering
...................................................................................................................
175
12.1 Content Filtering Overview
.............................................................................................
175
12.2 Configuring Keyword Blocking
.......................................................................................
175
12.3 Configuring the Schedule
..............................................................................................
176
12.4 Configuring Trusted Computers
.....................................................................................
177
Chapter
13
Introduction to IPSec
............................................................................................................
179
13.1 VPN Overview
.................................................................................................................
179
13.1.1 IPSec
......................................................................................................................
179
13.1.2 Security Association
...............................................................................................
179
13.1.3 Other Terminology
..................................................................................................
179
13.1.4 VPN Applications
...................................................................................................
180
13.2 IPSec Architecture
...........................................................................................................
180
13.2.1 IPSec Algorithms
....................................................................................................
181
13.2.2 Key Management
...................................................................................................
181
13.3 Encapsulation
..................................................................................................................
181
13.3.1 Transport Mode
......................................................................................................
182
13.3.2 Tunnel Mode
.........................................................................................................
182