ZyXEL Communications ZyWALL 5 User Manual page 13

Chapter 10
Firewall Screens................................................................................................... 163
10.1 Access Methods .............................................................................................163
10.2 Firewall Policies Overview .............................................................................163
10.3 Rule Logic Overview ......................................................................................164
10.3.1 Rule Checklist .......................................................................................164
10.3.2 Security Ramifications ..........................................................................165
10.3.3 Key Fields For Configuring Rules .........................................................165
10.3.3.1 Action ..........................................................................................165
10.3.3.2 Service ........................................................................................165
10.3.3.3 Source Address ...........................................................................165
10.3.3.4 Destination Address ....................................................................165
10.4 Connection Direction Examples .....................................................................165
10.4.1 LAN To WAN Rules ..............................................................................166
10.4.2 WAN To LAN Rules ..............................................................................166
10.5 Alerts ..............................................................................................................167
10.6 Configuring Firewall .......................................................................................167
10.6.1 Rule Summary ......................................................................................170
10.6.2 Configuring Firewall Rules ....................................................................171
10.6.3 Configuring Custom Services ...............................................................174
10.7 Example Firewall Rule ...................................................................................174
10.8 Predefined Services .......................................................................................178
10.9 Anti-Probing ...................................................................................................180
10.10 DoS Thresholds ...........................................................................................181
10.10.1 Threshold Values ................................................................................182
10.10.2 Half-Open Sessions ............................................................................182
10.10.2.1 TCP Maximum Incomplete and Blocking Time .........................182
Chapter 11
Content Filtering Screens ................................................................................... 185
11.1 Content Filtering Overview .............................................................................185
11.1.1 Restrict Web Features ..........................................................................185
11.1.2 Create a Filter List .................................................................................185
11.1.3 Customize Web Site Access ................................................................185
11.2 General Content Filter Configuration ..............................................................185
11.3 Content Filtering with an External Database ..................................................188
11.4 Categories and Registering ............................................................................188
11.5 Customization .................................................................................................195
11.6 Customizing Keyword Blocking URL Checking ..............................................198
11.6.1 Domain Name or IP Address URL Checking ........................................198
11.6.2 Full Path URL Checking ........................................................................198
11.6.3 File Name URL Checking .....................................................................198
11.7 Content Filtering Cache ..................................................................................199
ZyWALL 5 User's Guide
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