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Chapter 10 Firewalls
NN47922-500
In summary, stateful inspection:
•
Allows all sessions originating from the LAN (local network) to the WAN
(Internet).
•
Denies all sessions originating from the WAN to the LAN.
Figure 50
Stateful inspection
shows the Business Secure Router’s default firewall rules in action, and
demonstrates how stateful inspection works. User A can initiate a Telnet session
from within the LAN and responses to this request are allowed. However, other
Telnet traffic initiated from the WAN is blocked.
Stateful inspection process
In the following example, the following sequence of events occurs when a TCP
packet leaves the LAN network through the firewall's WAN interface. The TCP
packet is the first in a session, and the packet's application layer protocol is
configured for a firewall rule inspection:
1
The packet travels from the firewall's LAN to the WAN.
2
The packet is evaluated against the interface's existing outbound access list,
and the packet is permitted (a denied packet is dropped at this point).
Business Secure Router
Summary of Contents for BSR222
Page 28: ...28 Tables NN47922 500 ...
Page 50: ...50 Chapter 2 Introducing the WebGUI NN47922 500 ...
Page 66: ...66 Chapter 3 Wizard setup NN47922 500 ...
Page 92: ...92 Chapter 5 System screens NN47922 500 ...
Page 104: ...104 Chapter 6 LAN screens NN47922 500 ...
Page 154: ...154 Chapter 9 Static Route screens NN47922 500 ...
Page 196: ...196 Chapter 11 Firewall screens NN47922 500 ...
Page 212: ...212 Chapter 13 VPN NN47922 500 Figure 68 Summary IP Policies ...
Page 256: ...256 Chapter 13 VPN NN47922 500 Figure 82 VPN Client Termination advanced ...
Page 260: ...260 Chapter 13 VPN NN47922 500 ...
Page 264: ...264 Chapter 14 Certificates NN47922 500 Figure 84 My Certificates ...
Page 290: ...290 Chapter 14 Certificates NN47922 500 Figure 95 Trusted remote host details ...
Page 314: ...314 Chapter 16 IEEE 802 1x NN47922 500 ...
Page 318: ...318 Chapter 17 Authentication server NN47922 500 Figure 107 Local User database edit ...
Page 326: ...326 Chapter 17 Authentication server NN47922 500 ...
Page 374: ...374 Chapter 20 Logs Screens NN47922 500 Figure 151 Log settings ...
Page 384: ...384 Chapter 20 Logs Screens NN47922 500 ...
Page 402: ...402 Chapter 22 Maintenance NN47922 500 Figure 170 Restart screen ...