About 75% of Syria’s internet network was cut off from the global internet for most of Friday 3 June, according to Renesys, a US firm that provides web intelligence.
The shutdown started at 6:35am local time, and within about 30 minutes, the routes to 40 of 59 Syrian networks were withdrawn from the global routing table.
Renysys said that the Internet in Syria depends on state-owned operator Syrian Telecom, which buys most of its international capacity from Turk Telekom and Deutsche Telekom, with some contribution from PCCW, Tata, and Telecom Italia.
The “network prefixes” that remained reachable on Friday included those belonging to the Syrian government, although Renysys added that many government websites were “slow to respond or down”.
The networks that were not reachable included all of the prefixes reserved for SyriaTel's 3G mobile data networks, and smaller ISPs including Sawa, INET, and Runnet, according to Renysys.
The internet services started to return at 22.00 local time on Friday, when seven of the 40 networks came back online. The rest of the networks returned at 07:00 local time on Saturday morning.
Renysys added that it did not know how the outage was coordinated, or whether specific regions or cities may have been affected more than others.
“News is filtering out of Syria very slowly. If Egypt and Libya's Internet outages are any guide, one might conclude that events on the street in Syria are reaching a tipping point,” Renysis said in a posting on its website.