Draytek 2800 Series 用户指南

下载
页码 197
 
Vigor2800 Series User’s Guide 
53
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 Unknown 
Protocol 
Check the box to activate the Block Unknown Protocol function. 
Individual IP packet has a protocol field in the datagram header to 
indicate the protocol type running over the upper layer. However, 
the protocol types greater than 100 are reserved and undefined at 
this time. Therefore, the router should have ability to detect and 
reject this kind of packets. 
Warning Messages 
We provide Syslog function for user to retrieve message from Vigor 
router. The user, as a Syslog Server, shall receive the report sending 
from Vigor router which is a Syslog Client. 
 
All the warning messages related to DoS defense will be sent to user 
and user can review it through Syslog daemon. Look for the 
keyword DoS in the message, followed by a name to indicate what 
kind of attacks is detected. 
 
 
 
 
3
3
.
.
4
4
.
.
7
7
 
 
U
U
R
R
L
L
 
 
C
C
o
o
n
n
t
t
e
e
n
n
t
t
 
 
F
F
i
i
l
l
t
t
e
e
r
r
 
 
Based on the list of user defined keywords, the URL Content Filter facility in Vigor router 
inspects the URL string in every outgoing HTTP request. No matter the URL string is found 
full or partial matched with a keyword, the Vigor router will block the associated HTTP 
connection.  
For example, if you add key words such as “sex”, Vigor router will limit web access to web 
sites or web pages such as “www.sex.com”, ”www.backdoor.net/images/sex/p_386.html”. 
Or you may simply specify the full or partial URL such as “www.sex.com” or “sex.com”. 
Also the Vigor router will discard any request that tries to retrieve the malicious code. 
Click Firewall and click URL Content Filter to open the setup page.