ZyXEL Communications Prestige 792H, User Manual

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Prestige 792H User’s Guide
Table of Contents xi
5.13 Configuring Advanced Modem Setup......................................................................................... 5-18
Chapter 6 Network Address Translation (NAT) ....................................................................................... 6-1
6.1 NAT Overview.............................................................................................................................. 6-1
6.1.1 NAT Definitions................................................................................................................... 6-1
6.1.2 What NAT Does................................................................................................................... 6-1
6.1.3 How NAT Works ................................................................................................................. 6-2
6.1.4 NAT Application.................................................................................................................. 6-2
6.1.5 NAT Mapping Types ........................................................................................................... 6-3
6.2 SUA (Single User Account) Versus NAT..................................................................................... 6-4
6.3 SUA Server ................................................................................................................................... 6-5
6.3.1 Port Forwarding: Services and Port Numbers ...................................................................... 6-5
6.3.2 Configuring Servers Behind SUA (Example) ...................................................................... 6-6
6.4 Selecting the NAT Mode............................................................................................................... 6-7
6.5 Configuring SUA Server............................................................................................................... 6-8
6.6 Configuring Address Mapping.................................................................................................... 6-10
6.7 Editing an Address Mapping Rule .............................................................................................. 6-12
Chapter 7 Dynamic DNS Setup.................................................................................................................. 7-1
7.1 Dynamic DNS ............................................................................................................................... 7-1
7.1.1 DynDNS Wildcard ............................................................................................................... 7-1
7.2 Configuring Dynamic DNS........................................................................................................... 7-1
Chapter 8 Firewall....................................................................................................................................... 8-1
8.1 Firewall Overview......................................................................................................................... 8-1
8.2 Types of Firewalls......................................................................................................................... 8-1
8.2.1 Packet Filtering Firewalls..................................................................................................... 8-1
8.2.2 Application-level Firewalls .................................................................................................. 8-1
8.2.3 Stateful Inspection Firewalls ................................................................................................ 8-2
8.3 Introduction to ZyXEL’s Firewall................................................................................................. 8-2
8.4 Denial of Service........................................................................................................................... 8-3
8.4.1 Basics ................................................................................................................................... 8-3
8.4.2 Types of DoS Attacks........................................................................................................... 8-4
8.5 Stateful Inspection......................................................................................................................... 8-7
8.5.1 Stateful Inspection Process................................................................................................... 8-8
8.5.2 Stateful Inspection and the Prestige ..................................................................................... 8-9
8.5.3 TCP Security ...................................................................................................................... 8-10
8.5.4 UDP/ICMP Security........................................................................................................... 8-10
8.5.5 Upper Layer Protocols........................................................................................................ 8-11
8.6 Guidelines for Enhancing Security with Your Firewall .............................................................. 8-11
8.6.1 Security In General............................................................................................................. 8-11
8.7 Packet Filtering Vs Firewall........................................................................................................ 8-12
8.7.1 Packet Filtering: ................................................................................................................. 8-13
8.7.2 Firewall .............................................................................................................................. 8-13
Chapter 9 Firewall Configuration.............................................................................................................. 9-1