Draytek Vigor2500V Manual page 71

300 packets per second and 10 seconds, respectively. A brief description
for each item in the DoS defense function is shown below.
Enable DoS Defense: Click the checkbox to activate the DoS
Defense Functionality.
Enable SYN flood defense: Click the checkbox to activate the SYN
flood defense function. If the amount of the TCP SYN packets
from the Internet exceeds the user-defined threshold value, the
Vigor router will be forced to discard randomly the sequent TCP
SYN packets in the user-defined timeout period. The main goal is
to protect the Vigor router against the TCP SYN packets that
intend to use up the router' s limited-resource. By default, the
threshold and timeout values are set to 300 packets per second
and 10 seconds, respectively.
Enable UDP flood defense: Click the checkbox to activate the UDP
flood defense function. Once the UDP packets from the Internet
exceed the user-defined threshold value, the router will be forced
to discard all sequent UDP packets in the user-defined timeout
period. The default setting for threshold and timeout are 300
packets per second and 10 seconds, respectively.
Enable ICMP flood defense: Click the checkbox to activate the ICMP
flood defense function. Similar to the UDP flood defense function,
the router will discard the ICMP echo requests coming from the
Internet, once they exceed the user-defined threshold (by default,
300 packets per second) in a period of time (by default, 10
second for timeout).
Enable Port Scan detection: Port scan attacks occur by sending
packets with different port numbers in an attempt to scanning the
available services that one port will respond. To examine such an
exploration behavior, please click the checkbox to activate the
Port Scan detection function in your Vigor router. The Vigor
Firewall
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