150
Chapter 11 Filter configuration
NN47923-501
are replaced on a connection-by-connection basis, which makes it impossible to
know the exact address and port on the wire. Therefore, the Business Secure
Router 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 Business Secure Router is
receiving and sending the packets; for example. the interface. The interface can be
an Ethernet port or any other hardware port, as illustrated in
Figure 69
.
Figure 69
Protocol and Device Filter Sets
Firewall Versus Filters
Firewall configuration is discussed in
Chapter 10, “Introducing the firewall,” on
page 131
chapters
of this manual. Further comparisons are also made between
filtering, NAT and the firewall.
Applying a Filter
This section shows you where to apply the filters after you design them. The
Business Secure Router already has filters to prevent NetBIOS traffic from
triggering calls, and block incoming Telnet, FTP and HTTP connections.
Note:
Nortel recommends that you apply filters if you do not activate
the firewall.
Содержание 252
Страница 13: ...Contents 13 Nortel Business Secure Router 252 Configuration Advanced SIP Register Server 337 RTP 337 Index 341 ...
Страница 14: ...14 Contents NN47923 501 ...
Страница 20: ...20 Figures NN47923 501 ...
Страница 24: ...24 Tables NN47923 501 ...
Страница 30: ...30 Preface NN47923 501 ...
Страница 42: ...42 Chapter 1 Getting to know your Nortel Business Secure Router 252 NN47923 501 ...
Страница 48: ...48 Chapter 2 Introducing the SMT NN47923 501 SMT menus at a glance Figure 6 SMT overview ...
Страница 72: ...72 Chapter 3 WAN and Dial Backup Setup NN47923 501 ...
Страница 80: ...80 Chapter 4 LAN setup NN47923 501 ...
Страница 84: ...84 Chapter 5 Internet access NN47923 501 ...
Страница 98: ...98 Chapter 6 Remote Node setup NN47923 501 ...
Страница 102: ...102 Chapter 7 IP Static Route Setup NN47923 501 ...
Страница 130: ...130 Chapter 9 Network Address Translation NAT NN47923 501 ...
Страница 156: ...156 Chapter 12 SNMP Configuration NN47923 501 ...
Страница 178: ...178 Chapter 14 System information and diagnosis NN47923 501 ...
Страница 198: ...198 Chapter 15 Firmware and configuration file maintenance NN47923 501 ...
Страница 212: ...212 Chapter 17 Remote Management NN47923 501 ...
Страница 232: ...232 Appendix B Triangle Route NN47923 501 ...
Страница 252: ...252 Appendix D PPPoE NN47923 501 ...
Страница 256: ...256 Appendix E Hardware specifications NN47923 501 ...
Страница 266: ...266 Appendix F IP subnetting NN47923 501 ...
Страница 308: ...308 Appendix H NetBIOS filter commands NN47923 501 ...
Страница 332: ...332 Appendix K Brute force password guessing protection NN47923 501 ...