ZyXEL Communications NXC5200 User Manual page 351

Flood Detection
Flood attacks saturate a network with useless data, use up all available
bandwidth, and therefore make communications in the network impossible.
ICMP Flood Attack
An ICMP flood is broadcasting many pings or UDP packets so that so much data is
sent to the system, that it slows it down or locks it up.
Smurf
A smurf attacker (A) floods a router (B) with Internet Control Message Protocol
(ICMP) echo request packets (pings) with the destination IP address of each
packet as the broadcast address of the network. The router will broadcast the
ICMP echo request packet to all hosts on the network. If there are numerous
hosts, this will create a large amount of ICMP echo request and response traffic.
If an attacker (A) spoofs the source IP address of the ICMP echo request packet,
the resulting ICMP traffic will not only saturate the receiving network (B), but the
network of the spoofed source IP address (C).
Figure 155 Smurf Attack
NXC5200 User's Guide
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