have prompted Internet users to engage in self-censoring and self-monitoring to avoid the state's ambiguous grounds for arrest. In February 2011 Syria stopped filtering YouTube, Facebook, and Twitter. Voice over Internet Protocol (VoIP) is blocked completely and requires a proxy or Virtual Private Network (VPN) to work around it. However, VoIP operators that utilize non-standard Session Initiation Protocol (SIP) ports may function behind Syria's proxy. Internet cafes, which are widespread and accessible to the public for a fee, can be used to access blocked sites. However, more restrictions have been placed on internet cafes, all public internet centers need operating approval from the security services, are required to keep detailed records of their customers' surfing habits, and people have been arrested after accessing blocked content. Shutdown of Syrian Internet In 2012, it was reported that all Internet connectivity between Syria and the outside world appeared to have ceased, as of 29 November 2012. This coincided with reported intense rebel activity inside Syria. Matthew Prince, CEO of Cloudflare, reported that three undersea communication cables in Tartous, Syria and a fourth land cable through Turkey were connecting Syria to the internet prior to the event. However, according to an August 2014 interview with Edward Snowden, the Internet blackout in Syria was related to a failed attempt by the U.S. National Security Agency (NSA) to infiltrate malware on a core router of one of the country's main Internet Service Providers (ISPs). References