ZyXEL Communications ZyXEL ZyWALL 5 - Manual (Page 11)

ZyWALL 5 User’s Guide
10
7.4.3 PPTP Encapsulation ...............................................................................133
7.5 Traffic Redirect .................................................................................................136
7.6 Configuring Traffic Redirect ..............................................................................136
7.7 Configuring Dial Backup ...................................................................................137
7.8 Advanced Modem Setup ..................................................................................141
7.8.1 AT Command Strings ..............................................................................141
7.8.2 DTR Signal .............................................................................................141
7.8.3 Response Strings ....................................................................................141
7.9 Configuring Advanced Modem Setup ..............................................................141
Chapter 8
DMZ Screens ........................................................................................................ 145
8.1 DMZ Overview .................................................................................................145
8.2 Configuring DMZ ..............................................................................................145
8.3 Configuring IP Alias ..........................................................................................147
8.4 DMZ Public IP Address Example .....................................................................149
8.5 DMZ Private and Public IP Address Example ..................................................150
8.6 Configuring Port Roles .....................................................................................150
Chapter 9
Firewalls................................................................................................................ 153
9.1 Firewall Overview .............................................................................................153
9.2 Types of Firewalls ............................................................................................153
9.2.1 Packet Filtering Firewalls ........................................................................153
9.2.2 Application-level Firewalls ......................................................................153
9.2.3 Stateful Inspection Firewalls ...................................................................154
9.3 Introduction to ZyXEL’s Firewall .......................................................................154
9.4 Denial of Service ..............................................................................................155
9.4.1 Basics .....................................................................................................155
9.4.2 Types of DoS Attacks .............................................................................156
9.4.2.1 ICMP Vulnerability ........................................................................158
9.4.2.2 Illegal Commands (NetBIOS and SMTP) ......................................158
9.4.2.3 Traceroute .....................................................................................159
9.5 Stateful Inspection ............................................................................................159
9.5.1 Stateful Inspection Process ....................................................................160
9.5.2 Stateful Inspection and the ZyWALL .......................................................161
9.5.3 TCP Security ...........................................................................................161
9.5.4 UDP/ICMP Security ................................................................................162
9.5.5 Upper Layer Protocols ............................................................................162
9.6 Guidelines For Enhancing Security With Your Firewall ....................................163
9.7 Packet Filtering Vs Firewall ..............................................................................163
9.7.1 Packet Filtering: ......................................................................................163
9.7.1.1 When To Use Filtering ...................................................................163