Chapter 10 Firewalls
167
Nortel Business Secure Router 252 Configuration — Basics
When to use filtering
1
To block or allow LAN packets by their MAC addresses.
2
To block or allow special IP packets that are neither TCP nor UDP, nor ICMP
packets.
3
To block or allow both inbound (WAN to LAN) and outbound (LAN to
WAN) traffic between the specific inside host or network A and outside host
or network B. If the filter blocks the traffic from A to B, it also blocks the
traffic from B to A. Filters cannot distinguish traffic originating from an
inside host or an outside host by IP address.
4
To block or allow IP trace route.
Firewall
•
The firewall inspects packet contents as well as their source and destination
addresses. Firewalls of this type employ an inspection module, applicable to
all protocols, that understands data in the packet is intended for other layers,
from the network layer (IP headers) up to the application layer.
•
The firewall performs stateful inspection. It takes into account the state of the
connections it handles, so that, for example, a legitimate incoming packet can
be matched with the outbound request for that packet and allowed in.
Conversely, an incoming packet masquerading as a response to a nonexistent
outbound request can be blocked.
•
The firewall uses session filtering, or smart rules, that enhance the filtering
process and control the network session rather than control individual packets
in a session.
•
The firewall provides e-mail service to notify you of routine reports and when
alerts occur.
When to use the firewall
1
To prevent DoS attacks and prevent hackers cracking your network.
2
A range of source and destination IP addresses as well as port numbers can be
specified within one firewall rule, making the firewall a better choice when
complex rules are required.
3
To selectively block or allow inbound or outbound traffic between inside host
or networks and outside host or networks. Remember that filters cannot
Содержание BSR252
Страница 28: ...28 Tables NN47923 500 ...
Страница 44: ...44 Chapter 1 Getting to know your Business Secure Router NN47923 500 ...
Страница 52: ...52 Chapter 2 Introducing the WebGUI NN47923 500 ...
Страница 70: ...70 Chapter 3 Wizard setup NN47923 500 ...
Страница 91: ...Chapter 5 System screens 91 Nortel Business Secure Router 252 Configuration Basics Figure 20 Time and Date ...
Страница 96: ...96 Chapter 5 System screens NN47923 500 ...
Страница 100: ...100 Chapter 6 LAN screens NN47923 500 Configuring IP Click LAN to open the IP screen Figure 22 LAN IP ...
Страница 111: ...Chapter 7 WAN screens 111 Nortel Business Secure Router 252 Configuration Basics Figure 26 WAN WAN ISP ...
Страница 114: ...114 Chapter 7 WAN screens NN47923 500 Figure 27 WAN IP ...
Страница 120: ...120 Chapter 7 WAN screens NN47923 500 Figure 31 Dial Backup Setup ...
Страница 128: ...128 Chapter 7 WAN screens NN47923 500 ...
Страница 152: ...152 Chapter 9 Static Route screens NN47923 500 ...
Страница 194: ...194 Chapter 11 Firewall screens NN47923 500 ...
Страница 210: ...210 Chapter 13 VPN NN47923 500 Figure 67 Summary IP Policies ...
Страница 222: ...222 Chapter 13 VPN NN47923 500 Figure 71 VPN Branch Office rule setup ...
Страница 231: ...Chapter 13 VPN 231 Nortel Business Secure Router 252 Configuration Basics Figure 72 VPN Branch Office IP Policy ...
Страница 249: ...Chapter 13 VPN 249 Nortel Business Secure Router 252 Configuration Basics Figure 78 VPN Client Termination ...
Страница 256: ...256 Chapter 13 VPN NN47923 500 Figure 81 VPN Client Termination advanced ...
Страница 260: ...260 Chapter 13 VPN NN47923 500 ...
Страница 264: ...264 Chapter 14 Certificates NN47923 500 Figure 83 My Certificates ...
Страница 270: ...270 Chapter 14 Certificates NN47923 500 Figure 85 My Certificate create ...
Страница 274: ...274 Chapter 14 Certificates NN47923 500 Figure 86 My Certificate details ...
Страница 282: ...282 Chapter 14 Certificates NN47923 500 Figure 89 Trusted CA details ...
Страница 298: ...298 Chapter 14 Certificates NN47923 500 ...
Страница 316: ...316 Chapter 16 IEEE 802 1x NN47923 500 ...
Страница 320: ...320 Chapter 17 Authentication server NN47923 500 Figure 106 Local User database edit ...
Страница 328: ...328 Chapter 17 Authentication server NN47923 500 ...
Страница 376: ...376 Chapter 20 Logs Screens NN47923 500 Figure 150 Log settings ...
Страница 386: ...386 Chapter 20 Logs Screens NN47923 500 ...
Страница 392: ...392 Chapter 21 Call scheduling screens NN47923 500 Figure 157 Applying Schedule Sets to a remote node ...
Страница 393: ...Chapter 21 Call scheduling screens 393 Nortel Business Secure Router 252 Configuration Basics ...
Страница 394: ...394 Chapter 21 Call scheduling screens NN47923 500 ...
Страница 409: ...Chapter 22 Maintenance 409 Nortel Business Secure Router 252 Configuration Basics Figure 170 Restart screen ...
Страница 410: ...410 Chapter 22 Maintenance NN47923 500 ...
Страница 430: ...430 Appendix A Troubleshooting NN47923 500 ...