Government Internet Shutdowns Cost $7.69B in 2024 1/24/25, 11:17 AM and then block all internet traffic to or from those IP addresses. As multiple websites and services can be hosted on a single IP address, this method of internet censorship often leads to unintentionally blocking more than was intended. Domain Name System (DNS) Filtering DNS filtering works in a similar way to IP blocking but is more precise as it targets the domain name rather than an IP address. Information associated with domain names, such as top10vpn.com , are stored in a database distributed across multiple DNS Servers. Browsers rely on intermediate services, called DNS resolvers, to perform DNS lookups for specific domains against these databases, and retrieve the relevant destination IP address of the server, which then lets the browser communicate with the server that holds the desired URL. ISPs can program these DNS resolvers to return incorrect information for particular DNS lookups, such as twitter.com not existing. When this happens, users are met with an error page instead of the website or app loading as normal. Deep Packet Inspection (DPI) DPI examines the full contents of the data packets making up internet traffic on a network to allow for blocking of specific content or applications. DPI relies on devices between the end user and the rest of the internet, known as middleboxes and which form a key role in internet censorship in places like China. Manufacturers include companies like Huawei and Allot. DPI is also very effective at throttling speeds for specific types of traffic, such as video or Voice Over Internet Protocol (VOIP). https://www.top10vpn.com/research/cost-of-internet-shutdowns/ Page 18 of 28