Draytek Vigor2850 Series, Руководство пользователя

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Vigor2850 Series User’s Guide
131
Enable ICMP flood
defense
Check the box to activate the ICMP flood defense function.
Similar to the UDP flood defense function, once if the
Threshold of ICMP packets from Internet has exceeded the
defined value, the router will discard the ICMP echo
requests coming from the Internet. The default setting for
threshold and timeout are 50 packets per second and 10
seconds, respectively.
Enable PortScan
detection
Port Scan attacks the Vigor router by sending lots of packets
to many ports in an attempt to find ignorant services would
respond. Check the box to activate the Port Scan detection.
Whenever detecting this malicious exploration behavior by
monitoring the port-scanning Threshold rate, the Vigor
router will send out a warning. By default, the Vigor router
sets the threshold as 150 packets per second.
Block IP options
Check the box to activate the Block IP options function.
The Vigor router will ignore any IP packets with IP option
field in the datagram header. The reason for limitation is IP
option appears to be a vulnerability of the security for the
LAN because it will carry significant information, such as
security, TCC (closed user group) parameters, a series of
Internet addresses, routing messages...etc. An eavesdropper
outside might learn the details of your private networks.
Block Land
Check the box to enforce the Vigor router to defense the
Land attacks. The Land attack combines the SYN attack
technology with IP spoofing. A Land attack occurs when an
attacker sends spoofed SYN packets with the identical
source and destination addresses, as well as the port number
to victims.
Block Smurf
Check the box to activate the Block Smurf function. The
Vigor router will ignore any broadcasting ICMP echo
request.
Block trace router
Check the box to enforce the Vigor router not to forward any
trace route packets.
Block SYN fragment
Check the box to activate the Block SYN fragment function.
The Vigor router will drop any packets having SYN flag and
more fragment bit set.
Block Fraggle Attack
Check the box to activate the Block fraggle Attack function.
Any broadcast UDP packets received from the Internet is
blocked.
Activating the DoS/DDoS defense functionality might
block some legal packets. For example, when you activate
the fraggle attack defense, all broadcast UDP packets
coming from the Internet are blocked. Therefore, the RIP
packets from the Internet might be dropped.
Block TCP flag scan
Check the box to activate the Block TCP flag scan function.
Any TCP packet with anomaly flag setting is dropped. Those
scanning activities include
no flag scan
,
FIN without ACK
scan
,
SYN FINscan
,
Xmas scan
and
full Xmas scan
.
Block Tear Drop
Check the box to activate the Block Tear Drop function.