Tuesday, November 18, 2014

China just blocked thousands of websites

The Chinese censorship authorities have DNS poisoned *edgecastcdn.net, which means all subdomains of edgecastcdn.net are blocked in China. EdgeCast is one of the largest Content Delivery Networks (CDN) in the world and provides its cloud services to thousands of websites and apps in China.
I have seen instances of “collateral damage” due to “collateral freedom” over the past few days and have received emails from some smaller website owners wondering why their non-sensitive sites are being blocked by the great firewall.

What's going on?

The disruption to EdgeCast’s service was noted by the company on their website on November 14, 2014, although I noticed a problem on November 12 and the first DNS poisoning on the 13th.
The company's status update still appears on their site:
Please be advised, we are experiencing issues with content delivery in the China region due to suddenly increased restrictions imposed by the Chinese Government. If you are receiving reports from end users not able to view content from within China, please contact our network Operations center to discuss the options available to you.

Some of the recent victims of collateral damage, all EdgeCast clients, include:
Sony Mobile’s global and Chinese sites are both blocked.
The Atlantic will, sadly, not be able to claim that their website was blocked due to the aggressive nature of their reporting on China.
The project website of Drupal (drupal.org) is blocked. Drupal is used as a back-end framework for many websites worldwide. Administrators of those websites in China will face disruptions when trying to update Drupal or install extensions.
Firefox browser add-ons are another victim. Firefox's addons.cdn.mozilla.net is hosted on EdgeCast. Firefox users in China will not be able to install any add-on for Firefox.
Gravatar is used by many websites to show profile images. The images are hosted on EdgeCast and any website that uses Gravatar in China will be displaying broken images.

Other blocked websites include speedtest.net and deviantart.com. It is hard to tell what websites may be affected because different sites might have different elements (i.e. images) that rely on EdgeCast. Anybody who appears on the EdgeCast customer list is potentially affected.


The great firewall (GFW) is attempting to block access to collateral freedom mirror sites, which are hosted in the global cloud infrastructure. GFW cannot distinguish traffic to the  mirror sites and other traffic to the cloud provider which means that they cannot block access to the mirror sites without blocking access to the all sites hosted by the CDN. This is forcing the authorities to make a decision between allowing uncensored access to the global internet or blocking global CDNs all together, which will come at a significant economic cost.


EdgeCast removed the status update on its website, but have published a blog post about their current problems in China:

We have been hearing from our CDN and Monitoring partners throughout the industry and our own customers that more sites, CDNs and networks are being filtered or blocked by the Great Firewall of China. This week we’ve seen the filtering escalate with an increasing number of popular web properties impacted and even one of our many domains being partially blocked… with no rhyme or reason as to why.
At Verizon EdgeCast we have put policies in place to help our customers mitigate the effects of this most recent filtering but expect this to be an ongoing issue for our customers seeking to reach Chinese users (users in China). For any customers who are seeing their delivery impacted, please log in to your EdgeCast portal. Here you will find instructions on your portal home page on how to best mitigate filtering or blocking.
For those of our customers who are frustrated by this, we share your frustration, as does the whole content delivery and hosting industry. Rest assured that we stay committed to work with our global ISP partners and do our best to mitigate the effects of these filtering policies to ensure a clear path to your users and customers in China.