A majority of Chinese Net users were on Tuesday unable to surf the Internet, according to comments later posted online.
Multiple domestic Domain Name System service providers revealed that the incident occurred around 3 pm, when abnormalities appeared to root servers of all generic top-level domain names in the country.
Tests conducted by several Internet security agencies suggested that a large amount of domestic traffic to the disrupted websites was rerouted to an IP address of a US company Dynamic Internet Technology in North Carolina.
Bill Xia, president of Dynamic, told the Global Times Tuesday that they are not involved in the incident.
An anonymous security expert told the Global Times that the incident is possibly caused by a hacker attack, but the real attacker remains unknown as the hacker could have used the Dynamic IP address as a shield.
Normal access to most websites resumed around 5 pm and current investigation has not determined the exact cause.