The evil bit is a fictional IPv4 packet header field proposed in RFC 3514, a humorous

April Fools' Day RFC April is the fourth month of the year in the Gregorian and Julian calendars. It is the first of four months to have a length of 30 days, and the second of five months to have a length of less than 31 days. April is commonly associated with ...

from 2003 authored by

Steve Bellovin Steven M. Bellovin is a researcher on computer networking and security. He has been a professor in the Computer Science department at Columbia University since 2005. Previously, Bellovin was a Fellow at AT&T Labs Research in Florham Park, New Jers ...

. The

RFC RFC may refer to: Computing * Request for Comments, a memorandum on Internet standards * Request for change, change management * Remote Function Call, in SAP computer systems * Rhye's and Fall of Civilization, a modification for Sid Meier's Civ ...

recommended that the last remaining unused bit, the "Reserved Bit" in the

IPv4 Internet Protocol version 4 (IPv4) is the fourth version of the Internet Protocol (IP). It is one of the core protocols of standards-based internetworking methods in the Internet and other packet-switched networks. IPv4 was the first version de ...

packet header, be used to indicate whether a packet had been sent with malicious intent, thus making

computer security Computer security, cybersecurity (cyber security), or information technology security (IT security) is the protection of computer systems and networks from attack by malicious actors that may result in unauthorized information disclosure, the ...

engineering an easy problem simply ignore any messages with the evil bit set and trust the rest.

Influence

The evil bit has become a synonym for all attempts to seek simple technical solutions for difficult human social problems which require the willing participation of malicious actors, in particular efforts to implement

Internet censorship Internet censorship is the legal control or suppression of what can be accessed, published, or viewed on the Internet. Censorship is most often applied to specific internet domains (such as Wikipedia.org) but exceptionally may extend to all Inte ...

using simple technical solutions. As a joke,

FreeBSD FreeBSD is a free and open-source Unix-like operating system descended from the Berkeley Software Distribution (BSD), which was based on Research Unix. The first version of FreeBSD was released in 1993. In 2005, FreeBSD was the most popular ...

implemented support for the evil bit that day but removed the changes the next day. A Linux patch implementing the iptables module "ipt_evil" was posted the next year. Furthermore, a patch for FreeBSD 7 is available and is kept up-to-date. There is extension for

XMPP Extensible Messaging and Presence Protocol (XMPP, originally named Jabber) is an open communication protocol designed for instant messaging (IM), presence information, and contact list maintenance. Based on XML (Extensible Markup Language), it ...

protocol
XEP-0076: Malicious Stanzas
, inspired by evil bit. This RFC has also been quoted in the otherwise completely serious RFC 3675, ".sex Considered Dangerous", which may have caused the proponents of

.xxx .xxx (pronounced "dot triple- ecks" or "dot ecks ecks ecks") is a sponsored top-level domain (sTLD) intended as a voluntary option for pornographic sites on the Internet. The sponsoring organization is the International Foundation for Online R ...

to wonder whether the

Internet Engineering Task Force The Internet Engineering Task Force (IETF) is a standards organization for the Internet and is responsible for the technical standards that make up the Internet protocol suite (TCP/IP). It has no formal membership roster or requirements and a ...

(IETF) was commenting on their application for a

top-level domain A top-level domain (TLD) is one of the domains at the highest level in the hierarchical Domain Name System of the Internet after the root domain. The top-level domain names are installed in the root zone of the name space. For all domains in ...

(TLD) the document was not related to their application. For April Fool's 2010,

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

added an &evil=true parameter to requests through the Ajax APIs.

References

{{IETF RFC 1st april 2003 in computing April Fools' Day jokes Computer network security Computer humor Censorship 2003 hoaxes

Influence

See also

References