P-870HW-I1 User’s Guide
300
Chapter 30 Filter Setup
30.4 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 ZyXEL Device 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 ZyXEL Device 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 190
Protocol and Device Filter Sets
30.5 Firewall Versus Filters
Firewall configuration is discussed in the
firewall
chapters
of this manual. Further
comparisons are also made between filtering, NAT and the firewall.
30.6 Applying a Filter
This section shows you where to apply the filter(s) after you design it (them). The ZyXEL
Device already has filters to prevent NetBIOS traffic from triggering calls, and block
incoming telnet, FTP and HTTP connections
.
Note:
If you do not activate the firewall, it is advisable to apply filters
30.6.1 Applying LAN Filters
LAN traffic filter sets may be useful to block certain packets, reduce traffic and prevent
security breaches. Go to menu 3.1 (shown next) and enter the number(s) of the filter set(s) that
you want to apply as appropriate. You can choose up to four filter sets (from twelve) by
entering their numbers separated by commas, e.g., 3, 4, 6, 11. Input filter sets filter incoming
traffic to the ZyXEL Device and output filter sets filter outgoing traffic from the ZyXEL
Device. For
PPPoE or PPTP encapsulation, you have the additional option of specifying
remote node call filter sets.
Summary of Contents for P-870HW-I Series
Page 2: ......
Page 7: ...P 870HW I1 User s Guide Safety Warnings 7 This product is recyclable Dispose of it properly...
Page 30: ...P 870HW I1 User s Guide 30 List of Figures...
Page 36: ...P 870HW I1 User s Guide 36 List of Tables...
Page 46: ...P 870HW I1 User s Guide 46 Chapter 1 Getting To Know Your ZyXEL Device...
Page 54: ...P 870HW I1 User s Guide 54 Chapter 2 Introducing the Web Configurator...
Page 76: ...P 870HW I1 User s Guide 76 Chapter 3 Connection Wizard...
Page 92: ...P 870HW I1 User s Guide 92 Chapter 5 Status Screen...
Page 114: ...P 870HW I1 User s Guide 114 Chapter 6 Wireless LAN...
Page 115: ...P 870HW I1 User s Guide Chapter 6 Wireless LAN 115...
Page 116: ...P 870HW I1 User s Guide 116 Chapter 6 Wireless LAN...
Page 117: ...P 870HW I1 User s Guide Chapter 6 Wireless LAN 117...
Page 118: ...P 870HW I1 User s Guide 118 Chapter 6 Wireless LAN...
Page 126: ...P 870HW I1 User s Guide 126 Chapter 7 WAN...
Page 146: ...P 870HW I1 User s Guide 146 Chapter 10 NAT...
Page 158: ...P 870HW I1 User s Guide 158 Chapter 11 Firewalls Figure 87 Security Firewall Rules Edit...
Page 168: ...P 870HW I1 User s Guide 168 Chapter 12 Content Filter...
Page 196: ...P 870HW I1 User s Guide 196 Chapter 14 Static Route...
Page 228: ...P 870HW I1 User s Guide 228 Chapter 17 UPnP...
Page 236: ...P 870HW I1 User s Guide 236 Chapter 18 System...
Page 246: ...P 870HW I1 User s Guide 246 Chapter 20 Tools...
Page 256: ...P 870HW I1 User s Guide 256 Chapter 22 General Setup...
Page 258: ...P 870HW I1 User s Guide 258 Chapter 23 WAN Setup...
Page 266: ...P 870HW I1 User s Guide 266 Chapter 24 LAN Setup...
Page 286: ...P 870HW I1 User s Guide 286 Chapter 29 NAT Setup...
Page 304: ...P 870HW I1 User s Guide 304 Chapter 30 Filter Setup...
Page 306: ...P 870HW I1 User s Guide 306 Chapter 31 Firewall Setup...
Page 308: ...P 870HW I1 User s Guide 308 Chapter 32 SNMP Configuration...
Page 332: ...P 870HW I1 User s Guide 332 Chapter 35 System Maintenance 24 5 24 7...
Page 346: ...P 870HW I1 User s Guide 346 Chapter 37 IP Routing Policy Setup...
Page 364: ...P 870HW I1 User s Guide 364 Appendix A Product Specifications...
Page 390: ...P 870HW I1 User s Guide 390 Appendix D NAT...
Page 396: ...P 870HW I1 User s Guide 396 Appendix E Firewall Commands...
Page 434: ...P 870HW I1 User s Guide 434 Appendix I Services...