ZyXEL Communications P-2608HWL-Dx Series - Manual (Page 16)

P-2608HWL-Dx Series User’s Guide
16 Table of Contents
Chapter 13
Phone Book .......................................................................................................... 177
13.1 Phone Book Overview ....................................................................................177
13.2 Speed Dial Screen .........................................................................................177
13.3 Incoming Call Policy Screen ..........................................................................179
13.4 Group Ring Screen ........................................................................................181
Chapter 14
PSTN Line ............................................................................................................. 185
14.1 PSTN Line Overview ......................................................................................185
14.2 PSTN Line Screen .........................................................................................185
Chapter 15
Firewalls................................................................................................................ 187
15.1 Firewall Overview ..........................................................................................187
15.2 Types of Firewalls ..........................................................................................187
15.2.1 Packet Filtering Firewalls ......................................................................187
15.2.2 Application-level Firewalls ....................................................................188
15.2.3 Stateful Inspection Firewalls ................................................................188
15.3 Introduction to ZyXEL’s Firewall .....................................................................188
15.3.1 Denial of Service Attacks ......................................................................189
15.4 Denial of Service ............................................................................................189
15.4.1 Basics ...................................................................................................189
15.4.2 Types of DoS Attacks ...........................................................................190
15.4.2.1 ICMP Vulnerability ......................................................................192
15.4.2.2 Illegal Commands (NetBIOS and SMTP) ....................................192
15.4.2.3 Traceroute ...................................................................................193
15.5 Stateful Inspection ..........................................................................................193
15.5.1 Stateful Inspection Process ..................................................................194
15.5.2 Stateful Inspection on Your ZyXEL Device ...........................................194
15.5.3 TCP Security .........................................................................................195
15.5.4 UDP/ICMP Security ..............................................................................195
15.5.5 Upper Layer Protocols ..........................................................................196
15.6 Guidelines for Enhancing Security with Your Firewall ....................................196
15.6.1 Security In General ...............................................................................196
15.7 Packet Filtering Vs Firewall ............................................................................197
15.7.1 Packet Filtering: ....................................................................................197
15.7.1.1 When To Use Filtering .................................................................198
15.7.2 Firewall .................................................................................................198
15.7.2.1 When To Use The Firewall ..........................................................198