1.
Go to Objects > ALG > Add > HTTP ALG
2.
Specify a suitable name for the ALG, for example content_filtering
3.
Click the Web Content Filtering tab
4.
Select Enabled in the Mode list
5.
In the Blocked Categories list, select Search Sites and click the >> button.
6.
Click OK
Then, create a service object using the new HTTP ALG:
1.
Go to Local Objects > Services > Add > TCP/UDP service
2.
Specify a suitable name for the Service, for example http_content_filtering
3.
Select the TCP in the Type dropdown list
4.
Enter 80 in the Destination Port textbox
5.
Select the HTTP ALG just created in the ALG list
6.
Click OK
Finally, modify the NAT rule to use the new service:
1.
Go to Rules > IP Rules
2.
Select the NAT rule handling the HTTP traffic
3.
Select the Service tab
4.
Select the new service, http_content_filtering, in the predefined Service list
5.
Click OK
Dynamic content filtering is now activated for all web traffic from lannet to all-nets.
We can validate the functionality with the following steps:
1.
On a workstation on the lannet network, launch a standard web browser.
2.
Try to browse to a search site. For example, www.google.com.
3.
If everything is configured correctly, the web browser will present a web page that informs the user about that
the requested site is blocked.
Audit Mode
In Audit Mode, the system will classify and log all surfing according to the content filtering policy,
but restricted web sites will still be accessible to the users. This means the content filtering feature
of NetDefendOS can then be used as an analysis tool to analysis what categories of websites are
being accessed by a user community and how often.
After running in Audit Mode for some period of time, it is easier to then have a better understanding
of the surfing behavior of different user groups and also to better understand the potential impact of
turning on the WCF feature.
Introducing Blocking Gradually
Blocking websites can disturb users if it is introduced suddenly. It is therefore recommended that
the administrator gradually introduces the blocking of particular categories one at a time. This
allows individual users time to get used to the notion that blocking exists and could avoid any
adverse reaction that might occur if too much is blocked at once. Gradual introduction also makes it
6.3.4. Dynamic Web Content Filtering
Chapter 6. Security Mechanisms
303
Summary of Contents for NetDefend DFL-260E
Page 27: ...1 3 NetDefendOS State Engine Packet Flow Chapter 1 NetDefendOS Overview 27...
Page 79: ...2 7 3 Restore to Factory Defaults Chapter 2 Management and Maintenance 79...
Page 146: ...3 9 DNS Chapter 3 Fundamentals 146...
Page 227: ...4 7 5 Advanced Settings for Transparent Mode Chapter 4 Routing 227...
Page 241: ...5 4 IP Pools Chapter 5 DHCP Services 241...
Page 339: ...6 7 Blacklisting Hosts and Networks Chapter 6 Security Mechanisms 339...
Page 360: ...7 4 7 SAT and FwdFast Rules Chapter 7 Address Translation 360...
Page 382: ...8 3 Customizing HTML Pages Chapter 8 User Authentication 382...
Page 386: ...The TLS ALG 9 1 5 The TLS Alternative for VPN Chapter 9 VPN 386...
Page 439: ...Figure 9 3 PPTP Client Usage 9 5 4 PPTP L2TP Clients Chapter 9 VPN 439...
Page 450: ...9 7 6 Specific Symptoms Chapter 9 VPN 450...
Page 488: ...10 4 6 Setting Up SLB_SAT Rules Chapter 10 Traffic Management 488...
Page 503: ...11 6 HA Advanced Settings Chapter 11 High Availability 503...
Page 510: ...12 3 5 Limitations Chapter 12 ZoneDefense 510...
Page 533: ...13 9 Miscellaneous Settings Chapter 13 Advanced Settings 533...
