In other words, the GS block can disable communications with groups of IP addresses and even multiple subnets connected through many international channels related to targets. Meanwhile, blocks by the Great Firewall or GS apply not only to individual IP addresses which are targeted by transmission Control Protocol (TCP) Reset, but also to larger groups of IP addresses that include the targets. The Great Firewall is also known to selectively engage in Domain Name System (DNS) cache poisoning when particular sites are requested.
SUDDEN ATTACK VPN WINDOWS
“The Great Firewall” consists of so-called standard firewalls (e.g., Windows firewall) and proxy servers located at China’s main Internet gateways. Packets coming from foreign IP addresses are prevented from being routed through. A subsystem of the Golden Shield, which is known as “the Great Firewall” ( ) blocks access to the Internet. For instance, the Golden Shield (GS) is a Chinese surveillance project that manages connections to and from foreign countries. In some countries, international communication channels of the Internet are continuously monitored by governmental agencies and can be suddenly restricted. Three early studies reported blocks for BitTorrent or for general traffic based on port numbers. Nowadays, the open Internet is no longer transparent due to providers’ differentiation of traffics, restriction by governmental agencies (authorities or organizations), and network outages caused by cyber-attacks. Because of the cost, such services are usually accessed via the open (ordinary or public) Internet. Smooth and efficient web-based video conferences with offices in other countries are also important for the business activity of many multinational enterprises. It has become common for offshore business to utilize remote or cloud computers located in their motherland to achieve higher efficiency, safety and dependability (e.g., recovery from disaster or serious failure). Furthermore, 2–3 years’ successful usage of our tool in more than fifty offices confirms our method’s stable and dependable communication as well as its reasonable cost. Our method is validated by quantitative analysis on latency data corresponding to real GS blocks. (3) Asymmetrically, non-differential threshold value and elapsed time are used to determine the end of restriction and switch back to the open (ordinary or public) Internet. Our method predicts and avoids intentional blocks or restriction as follows: (1) the onset of the restriction is predicted or recognized in the early stage, using differential calculus of RTT, (2) immediate switching to Virtual Private Network (VPN) bypass is automatically performed before serious increase in network latency is experienced by users. To avoid this, we propose a network virtualization method and tool based on recognizing step-wise increases of Round Trip Time (RTT) that are caused by intentionally blocking international communication links. Temporary blocks or more permanent barriers as China’s Golden Shield (GS) are known to introduce significant network latency or Quality of Service (QoS) degradation that may hinder offshore business. However, in some countries, governmental agencies or organizations may suddenly block international communication links. Accessing offshore cloud or remote computers via the Internet has become popular.