ZyXEL Communications ZyAIR B-5000, User Manual

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ZyAIR B-5000 User’s Guide
28-6 Firewall
Figure 28-4 Smurf Attack
4. Often, many DoS attacks also employ a technique known as " IP Spoofing " as part of their attack. IP
Spoofing may be used to break into systems, to hide the hacker's identity, or to magnify the effect of the
DoS attack. IP Spoofing is a technique used to gain unauthorized access to computers by tricking a
router or firewall into thinking that the communications are coming from within the trusted network. To
engage in IP spoofing, a hacker must modify the packet headers so that it appears that the packets
originate from a trusted host and should be allowed through the router or firewall. The ZyAIR blocks all
IP Spoofing attempts.
5. An IP Zero Length Attack is the use of data sizes zero times a normal packet to flood the
communications that are coming from within a trusted network. These data packets are checked and the
victim network wastes time in attempting to do so.
28.5 Enabling the Firewall
The default rules allow LAN-to-WAN traffic and return traffic from the WAN when the connection initiated
from the LAN. You may allow traffic initiated from the WAN by configuring port-forwarding rules
discussed in
section 28.6. Click FIREWALL and GENERAL to open the General Parameters screen.