Blocking and unblocking of WebsitesDocument Transcript
Blocking and unblocking of Websites
The facility to block and unblock websites can be done at three levels:
• Global (blocks or unblocks a site for the whole Grid examples being
sex.com and bbc.co.uk)
• School (block or allows a site for a specific school at their request)
• LA (blocks or allows a site for all schools under their particular LA).
It should be noted that School lists override LA lists. The reason for this is
that individual schools such as faith schools may want some sites to be
blocked that the LA may allow for the rest of the schools under their control.
Filtering of web sites is done in two tiers. At the first tier, filtering is purely
done by “block” and “allow” lists which are updated manually. This is where
the majority of requests for blocking or unblocking of websites are applied.
The second tier is a content filtering layer. Any sites that do not match with
any lists at the first tier are passed to the second tier and the pages are
scanned for inappropriate material and scored depending on the words that
are contained on the page. Each location that takes a filtered internet feed
sits within a caste. The castes are as follows and each level has a different
score threshold: Primary, Secondary, Secondary + Games, Sixth Form, Staff,
and Social Networking. If the count of words and subsequent total score
exceeds the threshold set for the caste, the page is blocked. A block list
which is comprised of five separate daily downloaded lists from the internet is
also applied at this level.
If a school wishes to block or allow a particular site, they would contact their
local LA helpdesk with a request. The LA help desk would then pass that
request to YHGfL in one of three ways. The first way is by sending an e-mail
to firstname.lastname@example.org which will create an incident within Service-Now
(our ITIL framework service desk tool). The required detail within that e-mail
is: Location name, location contact & contact details (this is so that we can
check with the user at the location that the request is completed successfully)
and the site(s) that need to be blocked or allowed.
Requests for websites to be blocked or allowed is not an incident under the
ITIL Framework, it is a request for service or a standard change. This is why
this second method is the preferred way. All LA help desk staff have a user
account and password enabled within Service-Now which can be reached at
https://www.service-now.com/yhgfl which can be used to log requests from
within the service catalogue
Once the user is logged in, they are presented with the following self service
screen form which they can log incidents, view their existing incidents and
their progress etc as well as select “Catalogue” to log a service request
Once in the Service Catalogue, the user can select from the catalogue items
displayed (please note this list is being developed and is not exhaustive) such
as Block a website.
Details of the request can then be submitted straight into the tool.
The progress of the request can be monitored from within the tool by clicking
on My Requests within the Self-Service application.
The third method of submitting a request is by telephone. LA help desk
members can phone the YHGfL support team on 01724 275013.
On a normal request, we will look at the site in question and unless it is
specified in the request, we will take a view as to whether the site should be
blocked or allowed globally, at location or LA level. These requests will
usually be completed and available for the next morning meaning that some
forethought may be required to make sure a particular site is available for a
lesson. The facility to block immediately is currently available and any
emergency blocking of a site can be done within 30 minutes. Immediate
allowing of sites is not currently available, but is in development.
Changing caste to elevate privileges or bypassing filtering
There are different ways of elevating privileges or bypassing the filtering. For
a single session, getting to a particular site that is needed as a one off, such
as http://www.youtube.com or http://www.facebook.com, can be achieved by
navigating to http://login.yhgfl.net and entering the relevant username and
password to elevate privileges to the different caste levels as alluded to earlier
in the explanation of filtering, including an “unfiltered” level (unfiltered is as is
suggested by the name, but is still logged). These user names and
passwords are available from your LA help desk. The caste level would go
back to normal upon closing the browser. The default caste level for
location/school machines has been set by your LA and is achieved by
checking the source IP address of the accessing computer. Caste levels can
also be changed for specific machines, such as staff machines, or sixth form
machines by altering the proxy settings within your browser from
proxy.yhgfl.net on port 3128 to libproxy.yhgfl.net, with the port number
differing depending on the caste you want the machine to be in. This change
would permanently move the machine to that caste. These settings need to
be set by Group Policy Object within Active Directory in individual schools and
need to be sufficiently locked down so that pupils cannot alter their browser
settings and put themselves in the “unfiltered” caste which would give them
access to the full internet. A change request for this facility would need to be
submitted through the LA help desk as there are network changes that would
need to be performed to allow the school to access this service.
More detail on the filtering platform and how it works can be found here: http://
Change request forms can be found here:
Any further questions can be directed to:
Head of Support Services
T: 01724 275013