Domain Name System The Domain Name System (DNS) is a hierarchical and distributed name service that provides a naming system for computers, services, and other resources on the Internet or other Internet Protocol (IP) networks. It associates various information ...

blocking, or DNS blocking / filtering, is a strategy for making it difficult for users to locate specific domains or websites on the

Internet The Internet (or internet) is the Global network, global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a internetworking, network of networks ...

. It was first introduced in 1997 as a means to block

spam email Email spam, also referred to as junk email, spam mail, or simply spam, refers to unsolicited messages sent in bulk via email. The term originates from a Monty Python sketch, where the name of a canned meat product, "Spam," is used repetitively, m ...

from known malicious

IP address An Internet Protocol address (IP address) is a numerical label such as that is assigned to a device connected to a computer network that uses the Internet Protocol for communication. IP addresses serve two main functions: network interface i ...

es. DNS blocking can also be applied for outgoing requests as well. Instead of returning the valid

of a requested site (for example, instead of 198.35.26.96 being returned by the DNS when "www.wikipedia.org" is entered into a browser, if this IP were on a block list, the DNS might reply that the domain is unknown or with a different IP address that directs to a site with a page stating that the requested domain is not permitted). The latter case where the user is redirected to another destination would be considered

DNS Spoofing DNS spoofing, also referred to as DNS cache poisoning, is a form of computer security hacking in which corrupt Domain Name System data is introduced into the DNS resolver's cache, causing the name server to return an incorrect result record, e ...

, otherwise known as "DNS Poisoning". DNS blocking can be applied to individual servers/IP address, or entire blocks of IP addresses for multiple reasons. Some public DNS Resolvers, like

Quad9 Quad9 is a Public recursive name server, global public recursive Domain_Name_System, DNS Domain_Name_System#Recursive_and_caching_name_server, resolver that aims to protect users from malware and phishing. Quad9 is operated by the Quad9 Foundatio ...

and CleanBrowsing, offer filters as part of their DNS. Quad9, for example, blocks access to known phishing and malicious domains. CleanBrowsing filters out adult content in their effort to protect kids online.

Proposed legislation

In addition to its technical impact, DNS blocking also has many social and political implications.

Free speech Freedom of speech is a principle that supports the freedom of an individual or a community to articulate their opinions and ideas without fear of retaliation, censorship, or legal sanction. The right to freedom of expression has been recognise ...

and

due process Due process of law is application by the state of all legal rules and principles pertaining to a case so all legal rights that are owed to a person are respected. Due process balances the power of law of the land and protects the individual p ...

are key concerns regarding DNS blocking, particularly in the United States. DNS blocking was proposed to be mandated by the

Stop Online Piracy Act The Stop Online Piracy Act (SOPA) was a proposed United States congressional bill to expand the ability of U.S. law enforcement to combat online copyright infringement and online trafficking in counterfeit goods. Introduced on October 26, 20 ...

(SOPA) and the

PROTECT IP Act The PROTECT IP Act (Preventing Real Online Threats to Economic Creativity and Theft of Intellectual Property Act, or PIPA) was a proposed law with the stated goal of giving the US government and copyright holders additional tools to curb acce ...

(PIPA). It is a technique that essentially breaks the fundamental architecture of the internet. The goal for its use as intended by SOPA and PIPA is to prevent users from intentionally or unintentionally accessing web sites and web services that are known to host copyrighted material without authorization. According to an article in Network World magazine, "Just about universally, the people responsible for the technical development and operation of the Internet have said that the DNS-blocking proposals would break vital Internet technology while at the same time being entirely ineffectual against people who are serious about violating copyright laws and largely ineffectual against those who do so casually." They go on to claim that politicians who support this type of legislation are motivated by pressure from lobbyists and donors to their campaigns. These lobbyists and donors are often affiliated with special interest groups such as the

MPAA The Motion Picture Association (MPA) is an American trade association representing the five major film studios of the United States, the mini-major Amazon MGM Studios, as well as the video streaming services Netflix and Amazon Prime Video. F ...

and

RIAA The Recording Industry Association of America (RIAA) is a trade organization that represents the music recording industry in the United States. Its members consist of record labels and distributors that the RIAA says "create, manufacture, and/o ...

Criticism

Google Google LLC (, ) is an American multinational corporation and technology company focusing on online advertising, search engine technology, cloud computing, computer software, quantum computing, e-commerce, consumer electronics, and artificial ...

's chairman,

Eric Schmidt Eric Emerson Schmidt (born April 27, 1955) is an American businessman and former computer engineer who was the chief executive officer of Google from 2001 to 2011 and the company's chairman, executive chairman from 2011 to 2015. He also was the ...

, is quoted saying "I would be very, very careful if I were a government about arbitrarily mplementingsimple solutions to complex problems" in reference to DNS blocking and the PIPA bill. Experts claim that users could get around DNS blocking by using foreign search engines and foreign DNS servers. In fact, within two months of the legislation being introduced there were browser plug-ins released that enable users to resolve blocked domains. Numerous industry experts have concerns regarding the effect of DNS blocking on the security of the Internet. A former Bush administration Department of

Homeland Security Homeland security is an American national security term for "the national effort to ensure a homeland that is safe, secure, and resilient against terrorism and other hazards where American interests, aspirations, and ways of life can thrive" to ...

policy director claimed that altering the Domain Name System "would do great damage to internet security."

References

External links

* {{cite web , title=A Not-So-Brief History of DNS Blocking — And Why It Sucks, website=Wetmachine , date=2012-01-17 , url=https://wetmachine.com/tales-of-the-sausage-factory/a-not-so-brief-history-of-dns-blocking-and-why-it-sucks/ , ref={{sfnref , And Why It Sucks – Wetmachine , 2012 , access-date=2023-05-30
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