ZyXEL Communications P-2602H - Manual (Page 17)

Table of Contents
P-2602H(W)(L)-DxA User’s Guide
17
15.1 Access Methods .............................................................................................................. 207
15.2 General Firewall Policy Overview ................................................................................... 207
15.3 Rule Logic Overview ....................................................................................................... 208
15.3.1 Rule Checklist ........................................................................................................ 208
15.3.2 Security Ramifications ............................................................................................ 208
15.3.3 Key Fields For Configuring Rules .......................................................................... 209
15.4 Connection Direction ....................................................................................................... 209
15.4.1 LAN to WAN Rules ................................................................................................. 210
15.4.2 Alerts ...................................................................................................................... 210
15.5 General Firewall Policy ................................................................................................... 210
15.6 Firewall Rules Summary ..................................................................................................211
15.6.1 Configuring Firewall Rules ................................................................................... 213
15.6.2 Customized Services ............................................................................................ 216
15.6.3 Configuring A Customized Service ...................................................................... 216
15.7 Example Firewall Rule ..................................................................................................... 217
15.8 DoS Thresholds .............................................................................................................. 221
15.8.1 Threshold Values ................................................................................................... 221
15.8.2 Half-Open Sessions ............................................................................................... 222
15.8.3 Configuring Firewall Thresholds ............................................................................. 222
15.9 Firewall Commands ......................................................................................................... 224
Chapter 16
Content Filtering ................................................................................................................... 227
16.1 Content Filtering Overview ............................................................................................. 227
16.2 Configuring Keyword Blocking ....................................................................................... 227
16.3 Configuring the Schedule .............................................................................................. 228
16.4 Configuring Trusted Computers ..................................................................................... 229
Chapter 17
Introduction to IPSec............................................................................................................ 231
17.1 VPN Overview ................................................................................................................. 231
17.1.1 IPSec ...................................................................................................................... 231
17.1.2 Security Association ............................................................................................... 231
17.1.3 Other Terminology .................................................................................................. 231
17.1.4 VPN Applications ................................................................................................... 232
17.2 IPSec Architecture ........................................................................................................... 232
17.2.1 IPSec Algorithms .................................................................................................... 233
17.2.2 Key Management ................................................................................................... 233
17.3 Encapsulation .................................................................................................................. 233
17.3.1 Transport Mode ...................................................................................................... 234
17.3.2 Tunnel Mode ......................................................................................................... 234
17.4 IPSec and NAT ................................................................................................................ 234