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Barracuda Web Security Gateway

How can I block image search for common search engines using my Barracuda Web Filter?

  • Type: Knowledgebase
  • Date changed: 6 years ago

Solution #00006222

 

Scope:

Applies to all Barracuda Web Filter appliances on all versions of firmware.
 

Answer:
Common image search engines, such as Google, Bing, and Yahoo, can be blocked by the Barracuda Web Filter through various methods. Some of these search engines, for example, do not have a separate sub-domain for their image search service, which makes blocking by domain or URL impossible. In these circumstances, the search engines would require the URL Pattern feature to block access.


Below is the list of steps required to block image searches for these three common search engines:

Yahoo Image Search
1. Set the Content Filter category of Visual Search to be blocked. Configure this from Block/Accept>Content Filter in the Barracuda Web Filter web interface.
2. Alternately, you can block the domains images.search.yahoo.com and images.yahoo.com from under Block/Accept>Domains or Block/Accept Exceptions.

Bing Image Search
1. Bing does not have a sub-domain for its image searches. Configure this feature using URL patterns by navigating to Block/Accept>URL Patterns in the Barracuda Web Filter web interface. Ensure that the Unauthenticated policy is selected from the drop down menu on the top right part of the page.
2. Under Blocked Regular Expressions, in the Regular Expression column, add bing\.com/images.
3. In the message field, add the desired message a user should see when access to Bing Image Search is blocked and then click Add.
4. Switch to the Authenticated policy and perform steps 2 and 3.

Google Image Search
1. Google has a sub-domain for their image search, but does not use this if you first enter a search term using web search.
2. Set the Content Filter category of Visual Search to be blocked. Configure this from Block/Accept>Content Filter in the Barracuda Web Filter web interface. Alternately, block the domain images.google.com from under Block/Accept>Domains or Block/Accept Exceptions.
3. Navigate to Block/Accept>URL Patterns in the Barracuda Web Filter web interface. Ensure that the Unauthenticated policy is selected from the drop down menu on the top right part of the page.
4. Under Blocked Regular Expressions, in the Regular Expression column, add tbm=isch.
5. In the message field, add the desired message a user should see when blocked to Bing Image Search. Click Add.
6. Switch to the Authenticated policy and perform steps 4 and 5.


Additional Notes:

Search engines are constantly innovating and improving their system, so these methods are subject to change. Please contact Barracuda Support for more assistance if the listed methods do not work as expected.

Google allows users to search using both HTTP and HTTPS. While the above solution will block HTTP image searches in any deployment mode, any traffic over HTTPS will require SSL Inspection configuration. Otherwise the Barracuda Web Filter is unable to inspect the encrypted URL path. For more information on SSL Inspection and how to configure this, please see our Techlib article at http://techlib.barracuda.com/display/BWFv60/How+to+Configure+SSL+Inspection



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https://campus.barracuda.com/solution/501600000013LaFAAU