ZyXEL Communications P-2602HWLNI User Manual page 17

13.3.3 Call Forwarding ...................................................................................................... 228
13.3.4 Follow Me ............................................................................................................... 228
13.3.5 Call Pickup ............................................................................................................. 229
13.4 Checking the Device's IP Address ................................................................................... 229
13.5 Auto Firmware Upgrade .................................................................................................. 229
Part V: Security .................................................................................... 231
Chapter 14
Firewalls................................................................................................................................. 233
14.1 Firewall Overview ........................................................................................................... 233
14.2 Types of Firewalls ............................................................................................................ 233
14.2.1 Packet Filtering Firewalls ....................................................................................... 233
14.2.2 Application-level Firewalls ...................................................................................... 234
14.2.3 Stateful Inspection Firewalls .................................................................................. 234
14.3 Introduction to ZyXEL's Firewall ...................................................................................... 234
14.3.1 Denial of Service Attacks ....................................................................................... 235
14.4 Denial of Service ............................................................................................................. 235
14.4.1 Basics ..................................................................................................................... 235
14.4.2 Types of DoS Attacks ............................................................................................. 236
14.5 Stateful Inspection ........................................................................................................... 238
14.5.1 Stateful Inspection Process .................................................................................... 239
14.5.2 Stateful Inspection on Your ZyXEL Device ............................................................. 240
14.5.3 TCP Security .......................................................................................................... 240
14.5.4 UDP/ICMP Security ................................................................................................ 241
14.5.5 Upper Layer Protocols ........................................................................................... 241
14.6 Guidelines for Enhancing Security with Your Firewall ..................................................... 242
14.6.1 Security In General ................................................................................................ 242
14.7 Packet Filtering Vs Firewall ............................................................................................. 243
14.7.1 Packet Filtering: ..................................................................................................... 243
14.7.2 Firewall ................................................................................................................... 243
Chapter 15
Firewall Configuration .......................................................................................................... 245
15.1 Access Methods .............................................................................................................. 245
15.2 General Firewall Policy Overview ................................................................................... 245
15.3 Rule Logic Overview ....................................................................................................... 246
15.3.1 Rule Checklist ........................................................................................................ 246
15.3.2 Security Ramifications ............................................................................................ 246
15.3.3 Key Fields For Configuring Rules .......................................................................... 247
15.4 Connection Direction ....................................................................................................... 247
P-2602HWLNI User's Guide
Table of Contents
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