Draytek 2910 Betriebsanweisung

Seite von 235
 
Vigor2910 Series User’s Guide 
66 
C
C
o
o
n
n
t
t
e
e
n
n
t
t
 
 
S
S
e
e
c
c
u
u
r
r
i
i
t
t
y
y
 
 
M
M
a
a
n
n
a
a
g
g
e
e
m
m
e
e
n
n
t
t
 
 
(
(
C
C
S
S
M
M
)
)
 
 
As the popularity of all kinds of instant messenger application arises, communication cannot 
become much easier. Nevertheless, while some industry may leverage this as a great tool to 
connect with their customers, some industry may take reserve attitude in order to reduce 
employee misusage during office hour or prevent unknown security leak. It is similar 
situation for corporation towards peer-to-peer applications since file-sharing can be 
convenient but insecure at the same time. To address these needs, we provide CSM 
functionality.   
D
D
e
e
n
n
i
i
a
a
l
l
 
 
o
o
f
f
 
 
S
S
e
e
r
r
v
v
i
i
c
c
e
e
 
 
(
(
D
D
o
o
S
S
)
)
 
 
D
D
e
e
f
f
e
e
n
n
s
s
e
e
 
 
The DoS Defense functionality helps you to detect and mitigate the DoS attack. The attacks 
are usually categorized into two types, the flooding-type attacks and the vulnerability attacks. 
The flooding-type attacks will attempt to exhaust all your system's resource while the 
vulnerability attacks will try to paralyze the system by offending the vulnerabilities of the 
protocol or operation system. 
The DoS Defense function enables the Vigor router to inspect every incoming packet based 
on the attack signature database. Any malicious packet that might duplicate itself to paralyze 
the host in the secure LAN will be strictly blocked and a Syslog message will be sent as 
warning, if you set up Syslog server.   
Also the Vigor router monitors the traffic. Any abnormal traffic flow violating the pre-defined 
parameter, such as the number of thresholds, is identified as an attack and the Vigor router 
will activate its defense mechanism to mitigate in a real-time manner.   
The below shows the attack types that DoS/DDoS defense function can detect: 
1. SYN flood attack 
2. UDP flood attack 
3. ICMP flood attack 
4. TCP Flag scan 
5. Trace route 
6. IP options 
7. Unknown protocol 
8. Land attack 
9. Smurf attack 
10. SYN fragment 
11. ICMP fragment 
12. Tear drop attack 
13. Fraggle attack 
14. Ping of Death attack 
15. TCP/UDP port scan 
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
i
i
n
n
g
g
 
 
To provide an appropriate cyberspace to users, Vigor router equips with URL Content Filter 
not only to limit illegal traffic from/to the inappropriate web sites but also prohibit other web 
feature where malicious code may conceal.   
Once a user type in or click on an URL with objectionable keywords, URL keyword blocking 
facility will decline the HTTP request to that web page thus can limit user’s access to the 
website. You may imagine URL Content Filter as a well-trained convenience-store clerk 
who won’t sell adult magazines to teenagers. At office, URL Content Filter can also provide 
a job-related only environment hence to increase the employee work efficiency. How can 
URL Content Filter work better than traditional firewall in the field of filtering? Because it 
checks the URL strings or some of HTTP data hiding in the payload of TCP packets while 
legacy firewall inspects packets based on the fields of TCP/IP headers only. 
On the other hand, Vigor router can prevent user from accidentally downloading malicious 
codes from web pages. It’s very common that malicious codes conceal in the executable 
objects, such as ActiveX, Java Applet, compressed files, and other executable files. Once 
downloading these types of files from websites, you may risk bringing threat to your system. 
For example, an ActiveX control object is usually used for providing interactive web feature. 
If malicious code hides inside, it may occupy user’s system.