be logged. This page is known as the
restricted site notice
. The user is then free to continue to the
URL, or abort the request to prevent being logged.
By enabling this functionality, only users that have a valid reason to visit inappropriate sites will
normally do so. Other will avoid those sites due to the obvious risk of exposing their surfing
habits.
Caution: Overriding the restriction of a site
If a user overrides the restricted site notice page, they are allowed to surf to all pages
without any new restricted site message appearing again. However, the user is still
being logged. When the user has been inactive for 5 minutes, the restricted site page will
reappear if they then try to access a restricted site.
Reclassification of Blocked Sites
As the process of classifying unknown web sites is automated, there is always a small risk that
some sites are given an incorrect classification. NetDefendOS provides a mechanism for allowing
users to manually propose a new classification of sites.
This mechanism can be enabled on a per-HTTP ALG level, which means that the administrator
can choose to enable this functionality for regular users or for a selected user group only.
If reclassification is enabled and a user requests a web site which is disallowed, the block web
page will include a dropdown list containing all available categories. If the user believes the
requested web site is wrongly classified, he can select a more appropriate category from the
dropdown list and submit that as a proposal.
The URL to the requested web site as well as the proposed category will then be sent to D-Link's
central data warehouse for manual inspection. That inspection may result in the web site being
reclassified, either according to the category proposed or to a category which is felt to be correct.
Example 6.23. Reclassifying a blocked site
This example shows how a user may propose a reclassification of a web site if he believes it is
wrongly classified. This mechanism is enabled on a per-HTTP ALG level basis.
Command-Line Interface
First, create an HTTP Application Layer Gateway (ALG) Object:
gw-world:/> add ALG ALG_HTTP content_filtering
WebContentFilteringMode=Enable
FilteringCategories=SEARCH_SITES
AllowReclassification=Yes
Then, continue setting up the service object and modifying the
NAT
rule as we have done in the
previous examples.
Web Interface
First, create an HTTP Application Layer Gateway (ALG) Object:
1.
Go to: Objects > ALG > Add > HTTP ALG
2.
Specify a suitable name for the ALG, for example
content_filtering
Chapter 6: Security Mechanisms
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Содержание NetDefendOS
Страница 30: ...Figure 1 3 Packet Flow Schematic Part III Chapter 1 NetDefendOS Overview 30 ...
Страница 32: ...Chapter 1 NetDefendOS Overview 32 ...
Страница 144: ...Chapter 2 Management and Maintenance 144 ...
Страница 220: ... Enable DHCP passthrough Enable L2 passthrough for non IP protocols 4 Click OK Chapter 3 Fundamentals 220 ...
Страница 267: ... SourceNetwork lannet DestinationInterface any DestinationNetwork all nets 4 Click OK Chapter 3 Fundamentals 267 ...
Страница 284: ...Chapter 3 Fundamentals 284 ...
Страница 360: ...The ospf command options are fully described in the separate NetDefendOS CLI Reference Guide Chapter 4 Routing 360 ...
Страница 392: ...Chapter 4 Routing 392 ...
Страница 396: ...Web Interface 1 Go to Network Ethernet If1 2 Select Enable DHCP 3 Click OK Chapter 5 DHCP Services 396 ...
Страница 419: ... Host 2001 DB8 1 MAC 00 90 12 13 14 15 5 Click OK Chapter 5 DHCP Services 419 ...
Страница 420: ...Chapter 5 DHCP Services 420 ...
Страница 424: ...2 Now enter Name lan_Access Action Expect Interface lan Network lannet 3 Click OK Chapter 6 Security Mechanisms 424 ...
Страница 573: ...Chapter 6 Security Mechanisms 573 ...
Страница 575: ...This section describes and provides examples of configuring NAT and SAT rules Chapter 7 Address Translation 575 ...
Страница 607: ...Chapter 7 Address Translation 607 ...
Страница 666: ...Chapter 8 User Authentication 666 ...
Страница 775: ...Chapter 9 VPN 775 ...
Страница 819: ...Chapter 10 Traffic Management 819 ...
Страница 842: ...Chapter 11 High Availability 842 ...
Страница 866: ...Default Enabled Chapter 13 Advanced Settings 866 ...
Страница 879: ...Chapter 13 Advanced Settings 879 ...