Massive Overblocking Hits Hundreds Of UK Sites

from the well,-there's-a-surprise dept

Two years ago, Techdirt reported on a very troubling ruling in the UK courts that BT had to block access to the Usenet service provider Newzbin2. At the time, many feared that this would be the thin end of the wedge, giving copyright companies an easy way to shut down other sites. And with that power, of course, would come the inevitable errors, blocking completely unrelated sites. Just how seriously those mistakes could be is shown by this recent case of massive overblocking, reported here on PC Pro:

Virgin Media and Sky-owned Be Broadband customers found they were unable to access the Radio Times website last week, after the ISPs' anti-piracy filters included the site by accident. Telefonica, which still runs Be Broadband's network said that the overblocking had actually affected around 200 legitimate websites.
Radio Times is a well-known UK TV and radio listings magazine; another major site affected was the citizen science project Zooniverse. As an Open Rights Group (ORG) post explains, the specific Radio Times address that was blocked was, while continued to function. Here's why:
Many third-party load balanced systems, for example those using Amazon's AWS [Amazon Web Services] infrastructure, are enabled by pointing CNAME records at names controlled by those third-party systems. For example may be pointed at However, "" usually cannot be directly given a CNAME record (CNAME records cannot be mixed with the other record types needed such as those pointing to nameservers and mailservers). A common approach is to point "" to a server that merely redirects all requests to "".

From forum posts we can see that it's this redirection system, in this specific case an A record used for "", that has been blocked by the ISPs -- probably a court-order-blocked site is also using the service -- making numerous sites unavailable for any request made without the "www" prefix.
As ORG surmised, the problem arose from a UK court decision handed down last month that allowed the Football Association Premier League Limited to block FirstRow Sports, a site for live-streaming sports events. It turned out that the latter used the redirection service, which was then blocked as part of the court order. Unfortunately, hundreds of other sites, which also used that redirection service, were also blocked as a result.

This is a classic case of overblocking, but on a scale hitherto unseen in the UK. It shows why such Web blocks are very crude instruments, and how easily they can go wrong for quite subtle technical reasons. The problem is that the companies seeking the blocks can make mistakes, but the ISPs implementing the blocks don't want to become responsible for checking that the blocks are correct, and thus implement whatever is sent to them.

A post on the Zooniverse blog explains why this is so problematic:

The fact that the court could issue an order which didn’t see this coming and that the ISPs would act on it without checking that what they were doing was sensible is, in my opinion, extremely worrying. It shows how little power we as operators of a website have -- there are no guarantees that our hard work will travel along the little tubes that make up the internet to make it to your computer, and -- although Virgin were nice in this case -- it's disturbing to think we would have had no redress had they decided to keep blocking us. In the midst of a huge political argument in the UK about filtering content online, it's worth bearing in mind how a simple attempt by a multi-billion pound business to protect its revenue stream ended up, by complete and careless accident, preventing science getting done at the Zooniverse.
Sadly, we can probably expect things to get worse, as copyright companies resort to this approach more often, more mistakes are made, and more overblocks occur with little concern for the damage they cause.

Follow me @glynmoody on Twitter or, and on Google+

Filed Under: censorship, copyright, filters, overblocking
Companies: premiere league

Reader Comments

Subscribe: RSS

View by: Time | Thread

  1. icon
    That One Guy (profile), 15 Aug 2013 @ 3:57pm


    Or other words:

    'Your quick fixing of the problem brought about by our poorly thought out and implemented system, rather than waiting for us to ignore it and only fix it when it got enough press attention we could show off to made us look bad, don't do it again.'

Add Your Comment

Have a Techdirt Account? Sign in now. Want one? Register here

Subscribe to the Techdirt Daily newsletter

Comment Options:

  • Use markdown. Use plain text.
  • Remember name/email/url (set a cookie)

Follow Techdirt
Insider Shop - Show Your Support!

Report this ad  |  Hide Techdirt ads
Essential Reading
Techdirt Deals
Report this ad  |  Hide Techdirt ads
Techdirt Insider Chat
Report this ad  |  Hide Techdirt ads
Recent Stories
Report this ad  |  Hide Techdirt ads


Email This

This feature is only available to registered users. Register or sign in to use it.