Hello Andres,

N.B. Please take my answer with a huge grain of salt.

The google images search returns image results  (thumbnails) as inline base 64 
encoded images in the CSS. Selectively blocking them with any URL redirector 
will not work. It is possible to completely block google images but I assume 
this is not the way to follow for a school where a lot of pupil projects need 
access to the image search results.

Our current recommend the strategy for blocking explicit search results for 
schools are (please note you must be doing SSL decryption for this to work!):

- enforce Safe Search for Google. In this way proxy adds some special parameter 
to URL and some HTTP header to all outgoing requests to google servers asking 
it to show only safe images. Unfortunately this sometime misses quite offensive 
images as no safe search is safe enough.

- add keyword filtering to filter results of image search as it also contains 
some textual description of images and their original URLs that greatly 
improves detection rate. Some possible overblocking definitely will occur.

- add image tone detection filtering to the mix (works only for JPEGs for now 
and higly experimental) :(

In order to do that you need to integrate a content scanning server with your 
Squid - as possible variant consider taking a look at what we develop exactly 
for this purpose (search google for qlproxy ICAP - please note it is a 
commercial product).

Other choices are DansGuardian as parent proxy and SquidGuard/ufdbGuard/other 
redirectors.
I hope some other members of the list can explain how to do what your require 
with these.

Best regards,
Rafael


From: squid-users [mailto:squid-users-boun...@lists.squid-cache.org] On Behalf 
Of Andres Granados
Sent: Monday, May 18, 2015 7:50 PM
To: squid-users@lists.squid-cache.org
Subject: [squid-users] block inappropriate images of google

hello!
I need help on how to block pornographic images of google, I was trying 
different options and still do not succeed, try: http_reply_access with 
request_header_add, and even with a configuration dns, I think is to 
request_header_add the best, though not it has worked for me, I hope your help, 
is to implement a school, thanks!
_______________________________________________
squid-users mailing list
squid-users@lists.squid-cache.org
http://lists.squid-cache.org/listinfo/squid-users

Reply via email to