
Chapter 38 Filter Configuration
ZyWALL 2 Plus User’s Guide
552
After you’ve created the filter set, you must apply it.
1
Enter 11 from the main menu to go to menu 11.
2
Enter 1 or 2 to open
Menu 11.x - Remote Node Profile
.
3
Go to the
Edit Filter Sets
field, press
[SPACE BAR]
to select
Yes
and press
[ENTER]
.
4
This brings you to menu 11.1.4. Apply a filter set (our example filter set 3) as shown in
5
Press
[ENTER
] to confirm after you enter the set numbers and to leave menu 11.1.4.
38.4 Filter Types and NAT
There are two classes of filter rules,
Generic Filter
(Device) rules and protocol filter (
TCP/
IP
) rules. Generic filter rules act on the raw data from/to LAN and WAN. Protocol filter
rules
act on the IP packets. Generic and TCP/IP filter rules are discussed in more detail in the next
section. When NAT (Network Address Translation) is enabled, the inside IP address and port
number are replaced on a connection-by-connection basis, which makes it impossible to know
the exact address and port on the wire. Therefore, the ZyWALL applies the protocol filters to
the “native” IP address and port number before NAT for outgoing packets and after NAT for
incoming packets. On the other hand, the generic, or device filters are applied to the raw
packets that appear on the wire. They are applied at the point when the ZyWALL is receiving
and sending the packets; i.e. the interface. The interface can be an Ethernet port or any other
hardware port. The following diagram illustrates this.
Figure 378
Protocol and Device Filter Sets
38.5 Firewall Versus Filters
Below are some comparisons between the ZyWALL’s filtering and firewall functions.
38.5.1 Packet Filtering:
• The router filters packets as they pass through the router’s interface according to the filter
rules you designed.
• Packet filtering is a powerful tool, yet can be complex to configure and maintain,
especially if you need a chain of rules to filter a service.
• Packet filtering only checks the header portion of an IP packet.
Summary of Contents for ADSL 2+ Security Gateway
Page 2: ......
Page 25: ...Table of Contents ZyWALL 2 Plus User s Guide 25 Index 679 ...
Page 26: ...Table of Contents ZyWALL 2 Plus User s Guide 26 ...
Page 46: ...46 ...
Page 88: ...Chapter 3 Wizard Setup ZyWALL 2 Plus User s Guide 88 ...
Page 132: ...132 ...
Page 144: ...Chapter 6 LAN Screens ZyWALL 2 Plus User s Guide 144 ...
Page 180: ...Chapter 9 DMZ Screens ZyWALL 2 Plus User s Guide 180 ...
Page 190: ...190 ...
Page 222: ...Chapter 11 Firewall ZyWALL 2 Plus User s Guide 222 ...
Page 252: ...Chapter 13 Content Filtering Reports ZyWALL 2 Plus User s Guide 252 ...
Page 328: ...Chapter 16 Authentication Server ZyWALL 2 Plus User s Guide 328 ...
Page 330: ...330 ...
Page 346: ...Chapter 17 Network Address Translation NAT ZyWALL 2 Plus User s Guide 346 ...
Page 350: ...Chapter 18 Static Route ZyWALL 2 Plus User s Guide 350 ...
Page 398: ...Chapter 21 Remote Management ZyWALL 2 Plus User s Guide 398 ...
Page 416: ...Chapter 24 ALG Screen ZyWALL 2 Plus User s Guide 416 ...
Page 417: ...417 PART V Logs and Maintenance Logs Screens 419 Maintenance 447 ...
Page 418: ...418 ...
Page 423: ...Chapter 25 Logs Screens ZyWALL 2 Plus User s Guide 423 Figure 274 LOGS Log Settings ...
Page 466: ...466 ...
Page 474: ...Chapter 27 Introducing the SMT ZyWALL 2 Plus User s Guide 474 ...
Page 496: ...Chapter 30 LAN Setup ZyWALL 2 Plus User s Guide 496 ...
Page 504: ...Chapter 32 DMZ Setup ZyWALL 2 Plus User s Guide 504 ...
Page 508: ...Chapter 33 Wireless Setup ZyWALL 2 Plus User s Guide 508 ...
Page 556: ...Chapter 38 Filter Configuration ZyWALL 2 Plus User s Guide 556 ...
Page 570: ...Chapter 40 System Information Diagnosis ZyWALL 2 Plus User s Guide 570 ...
Page 586: ...Chapter 41 Firmware and Configuration File Maintenance ZyWALL 2 Plus User s Guide 586 ...
Page 594: ...Chapter 42 System Maintenance Menus 8 to 10 ZyWALL 2 Plus User s Guide 594 ...
Page 598: ...Chapter 43 Remote Management ZyWALL 2 Plus User s Guide 598 ...
Page 604: ...604 ...
Page 612: ...Chapter 45 Troubleshooting ZyWALL 2 Plus User s Guide 612 ...
Page 620: ...620 ...
Page 644: ...Appendix B Pop up Windows JavaScripts and Java Permissions ZyWALL 2 Plus User s Guide 644 ...
Page 668: ...Appendix E Importing Certificates ZyWALL 2 Plus User s Guide 668 ...
Page 672: ...Appendix F Legal Information ZyWALL 2 Plus User s Guide 672 ...
Page 678: ...Appendix G Customer Support ZyWALL 2 Plus User s Guide 678 ...