ZyXEL Communications Internet Security Gateway 10~100 Series User manual

ZyWALL 10~100 Series
Internet Security Gateway
Reference Guide
Versions 3.52, 3.60 and 3.61
March 2003

ZyWALL 10~100 Series Internet Security Gateway
ii Copyright
Copyright
Copyright © 2003 by ZyXEL Communications Corporation.
The contents of this publication may not be reproduced in any part or as a whole, transcribed, stored in a
retrieval system, translated into any language, or transmitted in any form or by any means, electronic,
mechanical, magnetic, optical, chemical, photocopying, manual, or otherwise, without the prior written
permission of ZyXEL Communications Corporation.
Published by ZyXEL Communications Corporation. All rights reserved.
Disclaimer
ZyXEL does not assume any liability arising out of the application or use of any products, or software
described herein. Neither does it convey any license under its patent rights nor the patent rights of others.
ZyXEL further reserves the right to make changes in any products described herein without notice.
This publication is subject to change without notice.
Trademarks
Trademarks mentioned in this publication are used for identification purposes only and may be properties of
their respective owners.

ZyWALL 10~100 Series Internet Security Gateway
FCC iii
Federal Communications Commission (FCC)
Interference Statement
This device complies with Part 15 of FCC rules. Operation is subject to the following two conditions:
This device may not cause harmful interference.
This device must accept any interference received, including interference that may cause undesired
operations.
This equipment has been tested and found to comply with the limits for a CLASS B digital device pursuant to
Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful
interference in a commercial environment. This equipment generates, uses, and can radiate radio frequency
energy, and if not installed and used in accordance with the instructions, may cause harmful interference to
radio communications.
If this equipment does cause harmful interference to radio/television reception, which can be determined by
turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of
the following measures:
Reorient or relocate the receiving antenna.
Increase the separation between the equipment and the receiver.
Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
Consult the dealer or an experienced radio/TV technician for help.
Notice 1
Changes or modifications not expressly approved by the party responsible for compliance could void the
user's authority to operate the equipment.
Certifications
Refer to the product page at www.zyxel.com.

ZyWALL 10~100 Series Internet Security Gateway
iv Information for Canadian Users
Information for Canadian Users
The Industry Canada label identifies certified equipment. This certification means that the equipment meets
certain telecommunications network protective, operation, and safety requirements. The Industry Canada
does not guarantee that the equipment will operate to a user's satisfaction.
Before installing this equipment, users should ensure that it is permissible to be connected to the facilities of
the local telecommunications company. The equipment must also be installed using an acceptable method of
connection. In some cases, the company's inside wiring associated with a single line individual service may
be extended by means of a certified connector assembly. The customer should be aware that the compliance
with the above conditions may not prevent degradation of service in some situations.
Repairs to certified equipment should be made by an authorized Canadian maintenance facility designated by
the supplier. Any repairs or alterations made by the user to this equipment, or equipment malfunctions, may
give the telecommunications company cause to request the user to disconnect the equipment.
For their own protection, users should ensure that the electrical ground connections of the power utility,
telephone lines, and internal metallic water pipe system, if present, are connected together. This precaution
may be particularly important in rural areas.
Caution
Users should not attempt to make such connections themselves, but should contact the appropriate electrical
inspection authority, or electrician, as appropriate.
Note
This digital apparatus does not exceed the class A limits for radio noise emissions from digital apparatus set
out in the radio interference regulations of Industry Canada.

ZyWALL 10~100 Series Internet Security Gateway
Warranty v
ZyXEL Limited Warranty
ZyXEL warrants to the original end user (purchaser) that this product is free from any defects in materials or
workmanship for a period of up to two years from the date of purchase. During the warranty period, and upon
proof of purchase, should the product have indications of failure due to faulty workmanship and/or materials,
ZyXEL will, at its discretion, repair or replace the defective products or components without charge for
either parts or labor, and to whatever extent it shall deem necessary to restore the product or components to
proper operating condition. Any replacement will consist of a new or re-manufactured functionally
equivalent product of equal value, and will be solely at the discretion of ZyXEL. This warranty shall not
apply if the product is modified, misused, tampered with, damaged by an act of God, or subjected to
abnormal working conditions.
NOTE
Repair or replacement, as provided under this warranty, is the exclusive remedy of the purchaser. This
warranty is in lieu of all other warranties, express or implied, including any implied warranty of
merchantability or fitness for a particular use or purpose. ZyXEL shall in no event be held liable for indirect
or consequential damages of any kind of character to the purchaser.
To obtain the services of this warranty, contact ZyXEL's Service Center for your Return Material
Authorization number (RMA). Products must be returned Postage Prepaid. It is recommended that the unit be
insured when shipped. Any returned products without proof of purchase or those with an out-dated warranty
will be repaired or replaced (at the discretion of ZyXEL) and the customer will be billed for parts and labor.
All repaired or replaced products will be shipped by ZyXEL to the corresponding return address, Postage
Paid. This warranty gives you specific legal rights, and you may also have other rights that vary from country
to country.
Online Registration
Register online registration at www.zyxel.com for free future product updates and information.

ZyWALL 10~100 Series Internet Security Gateway
vi Customer Support
Customer Support
When you contact your customer support representative please have the following information ready:
Please have the following information ready when you contact customer support.
• Product model and serial number.
• Information in Menu 24.2.1 – System Information.
• Warranty Information.
• Date that you received your device.
• Brief description of the problem and the steps you took to solve it.
METHOD
LOCATION
E-MAIL
SUPPORT/SALES
TELEPHONE/FAX WEB SITE/ FTP SITE REGULAR MAIL
[email protected]m.tw [phone] www.zyxel.com
www.europe.zyxel.com
WORLDWIDE
[e-mail] [phone] ftp.europe.zyxel.com
ZyXEL Communications Corp.,
6 Innovation Road II, Science-
Based Industrial Park, Hsinchu
300, Taiwan
[email protected]m [phone]
800-255-4101
www.zyxel.comNORTH
AMERICA
[e-mail] [phone] ftp.zyxel.com
ZyXEL Communications Inc.,
1650 Miraloma Avenue,
Placentia, CA 92870, U.S.A.
[email protected] [phone] www.zyxel.dkSCANDINAVIA
[e-mail] [phone] ftp.zyxel.dk
ZyXEL Communications A/S,
Columbusvej 5, 2860 Soeborg,
Denmark
[email protected] [phone] www.zyxel.deGERMANY
[e-mail] [phone]
ZyXEL Deutschland GmbH.
Adenauerstr. 20/A2 D-52146
Wuerselen, Germany

ZyWALL 10~100 Series Internet Security Gateway
Table of Contents vii
Table of Contents
Copyright......................................................................................................................................................ii
Federal Communications Commission (FCC) Interference Statement................................................. iii
Information for Canadian Users ...............................................................................................................iv
ZyXEL Limited Warranty ..........................................................................................................................v
Customer Support ......................................................................................................................................vi
List of Diagrams..........................................................................................................................................ix
List of Charts ...............................................................................................................................................x
Preface ........................................................................................................................................................xii
General Information ........................................................................................................................................ I
Chapter 1 Setting up Your Computer’s IP Address.............................................................................. 1-1
Chapter 2 Triangle Route........................................................................................................................ 2-1
Chapter 3 The Big Picture ...................................................................................................................... 3-1
Chapter 4 Wireless LAN and IEEE 802.11............................................................................................ 4-1
Chapter 5 Wireless LAN With IEEE 802.1x .........................................................................................5-1
Chapter 6 PPPoE ..................................................................................................................................... 6-1
Chapter 7 PPTP ....................................................................................................................................... 7-1
Chapter 8 IP Subnetting.......................................................................................................................... 8-1
Command and Log Information....................................................................................................................II
Chapter 9 Command Interpreter ........................................................................................................... 9-1
Chapter 10 Firewall Commands........................................................................................................... 10-1
Chapter 11 NetBIOS Filter Commands ................................................................................................11-1
Chapter 12 Boot Commands................................................................................................................. 12-1
Chapter 13 Log Descriptions ................................................................................................................ 13-1
Chapter 14 Brute-Force Password Guessing Protection .................................................................... 14-1
Index............................................................................................................................................................... III

ZyWALL 10~100 Series Internet Security Gateway
viii Table of Contents
Index ............................................................................................................................................................ A

ZyWALL 10~100 Series Internet Security Gateway
List of Diagrams ix
List of Diagrams
Diagram 2-1 Ideal Setup ................................................................................................................................ 2-1
Diagram 2-2 “Triangle Route” Problem ........................................................................................................ 2-2
Diagram 2-3 IP Alias...................................................................................................................................... 2-2
Diagram 2-4 Gateways on the WAN Side...................................................................................................... 2-3
Diagram 3-1 Big Picture— Filtering, Firewall, VPN and NAT ..................................................................... 3-1
Diagram 4-1 Peer-to-Peer Communication in an Ad-hoc Network................................................................ 4-3
Diagram 4-2 ESS Provides Campus-Wide Coverage..................................................................................... 4-4
Diagram 5-1 Sequences for EAP MD5–Challenge Authentication................................................................ 5-2
Diagram 6-1 Single-PC per Modem Hardware Configuration....................................................................... 6-1
Diagram 6-2 ZyWALL as a PPPoE Client ..................................................................................................... 6-2
Diagram 7-1 Transport PPP frames over Ethernet ......................................................................................... 7-1
Diagram 7-2 PPTP Protocol Overview .......................................................................................................... 7-2
Diagram 7-3 Example Message Exchange between PC and an ANT ............................................................ 7-3
Diagram 11-1 NetBIOS Display Filter Settings Command Without DMZ Example....................................11-2
Diagram 11-2 NetBIOS Display Filter Settings Command With DMZ Example.........................................11-2
Diagram 12-1 Option to Enter Debug Mode................................................................................................ 12-1
Diagram 12-2 Boot Module Commands ...................................................................................................... 12-2
Diagram 13-1 Example VPN Initiator IPSec Log...................................................................................... 13-12
Diagram 13-2 Example VPN Responder IPSec Log.................................................................................. 13-12

ZyWALL 10~100 Series Internet Security Gateway
x List of Charts
List of Charts
Chart 8-1 Classes of IP Addresses ..................................................................................................................8-1
Chart 8-2 Allowed IP Address Range By Class ..............................................................................................8-2
Chart 8-3 “Natural” Masks .............................................................................................................................8-2
Chart 8-4 Alternative Subnet Mask Notation..................................................................................................8-3
Chart 8-5 Subnet 1 ..........................................................................................................................................8-4
Chart 8-6 Subnet 2 ..........................................................................................................................................8-4
Chart 8-7 Subnet 1 ..........................................................................................................................................8-5
Chart 8-8 Subnet 2 ..........................................................................................................................................8-5
Chart 8-9 Subnet 3 ..........................................................................................................................................8-5
Chart 8-10 Subnet 4 ........................................................................................................................................8-6
Chart 8-11 Eight Subnets ................................................................................................................................8-6
Chart 8-12 Class C Subnet Planning...............................................................................................................8-7
Chart 8-13 Class B Subnet Planning...............................................................................................................8-7
Chart 10-1 Firewall Commands....................................................................................................................10-1
Chart 11-1 NetBIOS Filter Default Settings .................................................................................................11-2
Chart 13-1 System Error Logs ......................................................................................................................13-1
Chart 13-2 System Maintenance Logs..........................................................................................................13-1
Chart 13-3 UPnP Logs ..................................................................................................................................13-2
Chart 13-4 Content Filtering Logs................................................................................................................13-2
Chart 13-5 Attack Logs.................................................................................................................................13-2
Chart 13-6 Access Logs ................................................................................................................................13-5
Chart 13-7 ACL Setting Notes ......................................................................................................................13-9
Chart 13-8 ICMP Notes ..............................................................................................................................13-10
Chart 13-9 Sys log ......................................................................................................................................13-11
Chart 13-10 Sample IKE Key Exchange Logs ...........................................................................................13-13