The Chinese government has blocked access to all subdomains of edgecastcdn.net, one of the largest Content Delivery Networks (CDN) in the world and provides its cloud services to thousands of websites and apps in China. Greatfire.org, a group that conducts research on Chinese internet censorship, said the Chinese government have targeted a network operated by Edgecast, a subsidiary of Verizon Communications that delivers content and services for web companies.

Greatfire.org has used Edgecast to host "mirror sites" that redirect users to otherwise censored websites like YouTube.Websites that have been affected include Sony Mobile’s global and Chinese sites, The Atlantic will, the project website of Drupal (drupal.org) and Firefox browser add-ons.

Edgecast acknowledged the disruptions to its operations 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. 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)."

Verizon said any customers seeing their delivery impacted could log in to their EdgeCast portals and find instructions 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."