ZyXEL Communications ZyXEL ZyWALL 5 - Manual (Page 12)

ZyWALL 5 User’s Guide
11
9.7.2 Firewall ...................................................................................................164
9.7.2.1 When To Use The Firewall ............................................................164
Chapter 10
Firewall Screens................................................................................................... 165
10.1 Access Methods .............................................................................................165
10.2 Firewall Policies Overview .............................................................................165
10.3 Rule Logic Overview ......................................................................................166
10.3.1 Rule Checklist .......................................................................................166
10.3.2 Security Ramifications ..........................................................................167
10.3.3 Key Fields For Configuring Rules .........................................................167
10.3.3.1 Action ..........................................................................................167
10.3.3.2 Service ........................................................................................167
10.3.3.3 Source Address ...........................................................................167
10.3.3.4 Destination Address ....................................................................167
10.4 Connection Direction Examples .....................................................................167
10.4.1 LAN To WAN Rules ..............................................................................168
10.4.2 WAN To LAN Rules ..............................................................................168
10.5 Alerts ..............................................................................................................169
10.6 Configuring Firewall .......................................................................................169
10.6.1 Rule Summary ......................................................................................172
10.6.2 Configuring Firewall Rules ....................................................................173
10.6.3 Configuring Custom Services ...............................................................176
10.7 Example Firewall Rule ...................................................................................176
10.8 Predefined Services .......................................................................................180
10.9 Anti-Probing ...................................................................................................182
10.10 DoS Thresholds ...........................................................................................183
10.10.1 Threshold Values ................................................................................184
10.10.2 Half-Open Sessions ............................................................................184
10.10.2.1 TCP Maximum Incomplete and Blocking Time .........................184
Chapter 11
Content Filtering Screens ................................................................................... 187
11.1 Content Filtering Overview .............................................................................187
11.1.1 Restrict Web Features ..........................................................................187
11.1.2 Create a Filter List .................................................................................187
11.1.3 Customize Web Site Access ................................................................187
11.2 General Content Filter Configuration ..............................................................187
11.3 Content Filtering with an External Database ..................................................190
11.4 Categories and Registering ............................................................................190
11.5 Customization .................................................................................................197
11.6 Customizing Keyword Blocking URL Checking ..............................................200
11.6.1 Domain Name or IP Address URL Checking ........................................200