ZyXEL Communications P-2602HWLNI manual 17

		Table of Contents
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

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P-2602HWLNI User’s Guide