Draytek Vigor2500V Manual page 72

router will identify it and report a warning message if the
port-scanning rate in packets per second exceeds the
user-defined threshold value. By default, the Vigor router sets the
threshold as 300 packets per second to detect such a scanning
activity.
Enable Block IP options: Click it to activate the Block IP options
function. The Vigor router will ignore any IP packets with IP
option field appeared in the datagram header. The IP option
provides a way for hosts to send some significant information,
such as security, compartmentation, TCC (closed user group)
parameters,
messages...etc., which an outsider can analyze to learn details
about your private networks.
Enable Block Land: Click the associated checkbox and then enforce
the Vigor router to defense the Land attacks. The LAN attack
combines the SYN attack technology with IP spoofing. A Land
attack occurs when an attacker sends spoofed SYN packets
having the identical source and destination addresses, as well as
the port number, with those of the victim.
Enable Block Smurf: Click the checkbox to activate the Block Smurf
function. The Vigor router will reject any ICMP echo request
destined to the broadcast address.
Enable Block trace route: Click the checkbox to activate this
function. The Vigor router will not forward any trace route
packets.
Enable Block SYN fragment: Click the checkbox to activate the
Block SYN fragment function. Any packets having SYN flag and
more fragment bit set will be dropped.
Enable Block fraggle Attack: Click the checkbox to activate the
Firewall
a series of Internet
6-13
addresses, routing