Draytek 200 User Manual

Page of 144
 
VigorFly 200 Series User’s Guide 
83 
4
4
.
.
4
4
.
.
1
1
 
 
D
D
o
o
S
S
 
 
D
D
e
e
f
f
e
e
n
n
s
s
e
e
 
 
As a sub-functionality of IP Filter/Firewall, there are 5 types of detect/ defense function in the 
DoS Defense setup. The DoS Defense functionality is disabled for default. 
Click Firewall and click DoS Defense to open the setup page.   
 
Enable Dos Defense 
Check the box to activate the DoS Defense Functionality. 
Enable SYN flood defense
Check the box to activate the SYN flood defense function. 
Once detecting the Threshold of the TCP SYN packets from 
the Internet has exceeded the defined value, the Vigor 
router will start to randomly discard the subsequent TCP 
SYN packets for a period defined in Timeout. The goal for 
this is prevent the TCP SYN packets’ attempt to exhaust the 
limited-resource of Vigor router. By default, the threshold 
and timeout values are set to 50 packets per second and 10 
seconds, respectively. 
Enable UDP flood defense
Check the box to activate the UDP flood defense function. 
Once detecting the Threshold of the UDP packets from the 
Internet has exceeded the defined value, the Vigor router 
will start to randomly discard the subsequent UDP packets 
for a period defined in Timeout. The default setting for 
threshold and timeout are 150 packets per second and 10 
seconds, respectively. 
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 Furtive port 
scanner 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, the 
Vigor router will send out a warning.   
Enable Ping of Death 
Defense  
 
Check the box to activate the Block Ping of Death function. 
This attack involves the perpetrator sending overlapping 
packets to the target hosts so that those target hosts will 
hang once they re-construct the packets. The Vigor routers