Chapter 13 Firewall
device or network so users no longer have access to network resources. The ZyXEL Device is
DDoS
A DDoS attack is one in which multiple compromised systems attack a single target, thereby causing denial of service for users of the targeted system.
LAND Attack
In a LAND attack, hackers flood SYN packets into the network with a spoofed source IP address of the target system. This makes it appear as if the host computer sent the packets to itself, making the system unavailable while the target system tries to respond to itself.
Ping of Death
Ping of Death uses a "ping" utility to create and send an IP packet that exceeds the maximum 65,536 bytes of data allowed by the IP specification. This may cause systems to crash, hang or reboot.
SPI
Stateful Packet Inspection (SPI) tracks each connection crossing the firewall and makes sure it is valid. Filtering decisions are based not only on rules but also context. For example, traffic from the WAN may only be allowed to cross the firewall in response to a request from the LAN.
13.2 The Firewall Screen
Use this screen to enable firewall and/or SPI. Click Advanced Setup > Firewall to display the following screen.
Figure 44 Advanced Setup > Firewall
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