Troll (Internet)
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"Do not feed the trolls" and its abbreviation "DNFTT" redirect here. For the Wikimedia essay, see "What is a troll?".
The "trollface" sometimes used to indicate trolling.[1]
In Internet slang, a troll is someone who posts inflammatory[citation needed], extraneous, or off-topic messages in an online community, such as an online discussion forum, chat room, or blog, with the primary intent of provoking readers into an emotional response[2] or of otherwise disrupting normal on-topic discussion.[3] The noun troll may refer to the provocative message itself, as in: "That was an excellent troll you posted". While the word troll and its associated verb trolling are associated with Internet discourse, media attention in recent years has made such labels subjective, with trolling describing intentionally provocative actions outside of an online context. For example, mass media uses troll to describe "a person who defaces Internet tribute sites with the aim of causing grief to families."[4][5]
Contents show hidden text
* 1 Etymology
o 1.1 Early history
o 1.2 In other languages
* 2 Trolling, identity, and anonymity
* 3 Concern troll
* 4 Troll sites
* 5 Media coverage and controversy
* 6 Usage
* 7 Examples of trolling
* 8 See also
* 9 References
* 10 External links
Etymology
The verb troll originates from Old French troller, a hunting term. The noun troll comes from the Old Norse word for a mythological monster.[6]
In modern English usage, the verb troll is a fishing technique of slowly dragging a lure or baited hook from a moving boat.[7] The word evokes the trolls of Scandinavian folklore and children's tales, where they are often creatures bent on mischief and wickedness.
The contemporary use of the term is alleged to have appeared on the Internet in the late 1980s,[8] but the earliest known example is from 1992.[9] Early non-internet related use of trolling for actions deliberately performed to provoke a reaction can be found in the military; by 1972 the term trolling for MiGs was documented in use by US Navy pilots in Vietnam.[10]
Early history
The most likely derivation of the word troll can be found in the phrase "trolling for newbies", popularized in the early 1990s in the Usenet group, alt.folklore.urban (AFU).[11][12] Commonly, what is meant is a relatively gentle inside joke by veteran users, presenting questions or topics that had been so overdone that only a new user would respond to them earnestly. For example, a veteran of the group might make a post on the common misconception that glass flows over time. Long-time readers would both recognize the poster's name and know that the topic had been discussed a lot, but new subscribers to the group would not realize, and would thus respond. These types of trolls served as a practice to identify group insiders. This definition of trolling, considerably narrower than the modern understanding of the term, was considered a positive contribution.[11][13] One of the most notorious AFU trollers, Snopes,[11] went on to create his eponymous urban folklore website.
By the late 1990s, alt.folklore.urban had such heavy traffic and participation that trolling of this sort was frowned upon. Others expanded the term to include the practice of playing a seriously misinformed or deluded user, even in newsgroups where one was not a regular; these were often attempts at humor rather than provocation. In such contexts, the noun troll usually referred to an act of trolling, rather than to the author.
In other languages
In Icelandic, þurs (a thurs) or tröll (a troll) may refer to trolls, the verbs þursa (to troll) or þursast (to be trolling, to troll about) may used.
In Japanese, tsuri (つり) means "fishing" and refers to intentionally misleading posts whose only purpose is to get the readers to react, i.e. get trolled. arashi (あらし) means "laying waste" and can also be used to refer to simple spamming.
In Korean, nak-si (낚시) means "fishing", and is used to refer to Internet trolling attempts, as well as purposefully misleading post titles. A person who recognizes the troll after having responded (or, in case of a post title nak-si, having read the actual post) would often refer to himself as a caught fish.[citation needed]
In Thai, the term "krean" (เกรียน) has been adopted to address Internet trolls. The term literally refers to a closely cropped hairstyle worn by most school boys in Thailand, thus equating Internet trolls to school boys. The term "tob krean" (ตบเกรียน), or slapping a cropped head, refers to the act of posting intellectual replies to refute and cause the messages of Internet trolls to be unintelligent.[citation needed]
Trolling, identity, and anonymity
In academic literature, the practice of trolling was first documented by Judith Donath (1999). Donath's paper outlines the ambiguity of identity in a disembodied "virtual community" such as Usenet:
“ In the physical world there is an inherent unity to the self, for the body provides a compelling and convenient definition of identity. The norm is: one body, one identity ... The virtual world is different. It is composed of information rather than matter.[14] ”
Donath provides a concise overview of identity deception games which trade on the confusion between physical and epistemic community:
“ Trolling is a game about identity deception, albeit one that is played without the consent of most of the players. The troll attempts to pass as a legitimate participant, sharing the group's common interests and concerns; the newsgroups members, if they are cognizant of trolls and other identity deceptions, attempt to both distinguish real from trolling postings, and upon judging a poster a troll, make the offending poster leave the group. Their success at the former depends on how well they — and the troll — understand identity cues; their success at the latter depends on whether the troll's enjoyment is sufficiently diminished or outweighed by the costs imposed by the group.
Trolls can be costly in several ways. A troll can disrupt the discussion on a newsgroup, disseminate bad advice, and damage the feeling of trust in the newsgroup community. Furthermore, in a group that has become sensitized to trolling — where the rate of deception is high — many honestly naïve questions may be quickly rejected as trollings. This can be quite off-putting to the new user who upon venturing a first posting is immediately bombarded with angry accusations. Even if the accusation is unfounded, being branded a troll is quite damaging to one's online reputation.[14]
”
Susan Herring et al. in "Searching for Safety Online: Managing 'Trolling' in a Feminist Forum" point out the difficulty inherent in monitoring trolling and maintaining freedom of speech in online communities: "harassment often arises in spaces known for their freedom, lack of censure, and experimental nature".[15] Free speech may lead to tolerance of trolling behavior, complicating the members' efforts to maintain an open, yet supportive discussion area, especially for sensitive topics such as race, gender, and sexuality.[15]
In an effort to reduce uncivil behavior by increasing accountability, many web sites (e.g. Reuters, Facebook, and Gizmodo) now require commenters to register their names and e-mail addresses.[16]
Concern troll
A concern troll is a false flag pseudonym created by a user whose actual point of view is opposed to the one that the user claims to hold. The concern troll posts in Web forums devoted to its declared point of view and attempts to sway the group's actions or opinions while claiming to share their goals, but with professed "concerns". The goal is to sow fear, uncertainty and doubt within the group.[17]
An example of this occurred in 2006 when Tad Furtado, a staffer for then-Congressman Charles Bass (R-NH), was caught posing as a "concerned" supporter of Bass's opponent, Democrat Paul Hodes, on several liberal New Hampshire blogs, using the pseudonyms "IndieNH" or "IndyNH". "IndyNH" expressed concern that Democrats might just be wasting their time or money on Hodes, because Bass was unbeatable.[18][19]
Although the term "concern troll" originated in discussions of online behavior, it now sees increasing use to describe similar behaviors that take place offline.
For example, James Wolcott of Vanity Fair accused a conservative New York Daily News columnist of "concern troll" behavior in his efforts to downplay the Mark Foley scandal. Wolcott links what he calls concern trolls to Saul Alinsky's "Do-Nothings", giving a long quote from Alinsky on the Do-Nothings' method and effects:
“ These Do-Nothings profess a commitment to social change for ideals of justice, equality, and opportunity, and then abstain from and discourage all effective action for change. They are known by their brand, 'I agree with your ends but not your means.'[20] ”
The Hill published an op-ed piece by Markos Moulitsas of the liberal blog Daily Kos titled "Dems: Ignore 'Concern Trolls' ". The concern trolls in question were not Internet participants; they were Republicans offering public advice and warnings to the Democrats. The author defines "concern trolling" as "offering a poisoned apple in the form of advice to political opponents that, if taken, would harm the recipient".[21]
Troll sites
While many webmasters and forum administrators consider trolls a scourge on their sites, some websites welcome them. For example, a New York Times article discussed troll activity at 4chan and at Encyclopedia Dramatica, which it described as "an online compendium of troll humor and troll lore".[8] This site and others are often used as a base to troll against sites that their members can not normally post on. These trolls feed off the reactions of their victims because "their agenda is to take delight in causing trouble".[22]
Media coverage and controversy
Mainstream media outlets have focused their attention on the willingness of some Internet trolls to go to extreme lengths in their attempts at eliciting reactions.
On March 31, 2010, the Today Show ran a segment detailing the deaths of three separate adolescent girls and trolls’ subsequent reactions to their deaths. Shortly after the suicide of high school student Alexis Pilkington, anonymous posters began trolling for reactions across various message boards, referring to Pilkington as a “suicidal slut,” and posting graphic images on her Facebook memorial page. The segment also included an expose of a 2006 accident, in which an eighteen-year old fatally crashed her father’s car into a highway pylon; trolls emailed her grieving family the leaked pictures of her mutilated corpse.[5]
In February 2010, the Australian government became involved after trolls defaced the Facebook tribute pages of murdered children Trinity Bates and Elliott Fletcher. Australian communications minister Stephen Conroy decried the attacks, committed mainly by 4chan users, as evidence of the need for greater Internet regulation, stating, “This argument that the Internet is some mystical creation that no laws should apply to, that is a recipe for anarchy and the wild west.”[23] Conroy has been noted in the past for his advocacy of Internet censorship. In the wake of these events, Facebook responded by strongly urging administrators to be aware of ways to ban users and remove inappropriate content from Facebook pages.[24]
Usage
Application of the term troll is subjective. Some readers may characterize a post as trolling, while others may regard the same post as a legitimate contribution to the discussion, even if controversial. Like any pejorative term, it can be used as an ad hominem attack, suggesting a negative motivation.
Regardless of the circumstances, controversial posts may attract a particularly strong response from those unfamiliar with the robust dialogue found in some online, rather than physical, communities. Experienced participants in online forums know that the most effective way to discourage a troll is usually to ignore it, because responding tends to encourage trolls to continue disruptive posts — hence the often-seen warning: "Please do not feed the trolls".
Examples of trolling
A prank cake using common troll motifs such as the acronym "YHBT" (You Have Been Trolled), the term "pwned", and Guy Fawkes masks.
So-called Gold Membership trolling originated in 2007 on 4chan boards, users posting fake images claiming to offer upgraded 4chan account privileges; without a “Gold” account, one could not view certain content. This turned out to be a hoax designed to fool board members, especially newcomers. It was copied and became an Internet meme. In some cases, this type of troll has been used as a scam, most notably on Facebook, where fake Facebook Gold Account upgrade ads have proliferated in order to link users to dubious websites and other content.[25]
As reported on April 8, 1999, investors became victims of trolling via an online financial discussion regarding PairGain, a telephone equipment company based in California. Trolls operating in the stock’s Yahoo Finance chat room posted a fabricated Bloomberg News article stating that an Israeli telecom company could potentially acquire PairGain. As a result, PairGain’s stock jumped by 31%. However, the stock promptly crashed after the reports were identified as false.[26]
The case of Zeran v. America Online, Inc. resulted primarily from trolling. Six days after the Oklahoma City bombing, anonymous users posted advertisements for shirts celebrating the bombing on AOL message boards, claiming that the shirts could be obtained by contacting Mr. Kenneth Zeran. The posts listed Zeran’s address and home phone number. Zeran was subsequently harassed.[26]
Anti-Scientology protests by Anonymous, commonly known as Project Chanology, are sometimes labeled as "trolling" by media such as Wired,[27] and the participants sometimes explicitly self-identify as "trolls".
See also
Crystal Clear app browser.png Internet portal
External links
Look up troll in Wiktionary, the free dictionary.
Wikimedia Commons has media related to: Trolls (Internet)
Wikinews has related news: UK court jails man for trolling online tribute pages
* Usenet and Bulletin Board Abuse at the Open Directory Project
* Article on trolls and the 'art' of trolling by Steve Myers
* What is a troll? from the Straight Dope
* Trolling lore and essays
* Searching for Safety Online: Managing "Trolling" in a Feminist Forum
* Malwebolence – The World of Web Trolling; New York Times Magazine, By Mattathias Schwartz; August 3, 2008.
* The relationship between social context cues and uninhibited verbal behavior in computer-mediated communication
* The Subtle Art of Trolling
* A Discussion on Flaming from New Scientist Technology Blog
An Internet Protocol address (IP address) is a numerical label assigned to each device (e.g., computer, printer) participating in a computer network that uses the Internet Protocol for communication.[1] An IP address serves two principal functions: host or network interface identification and location addressing. Its role has been characterized as follows: "A name indicates what we seek. An address indicates where it is. A route indicates how to get there."[2]
The designers of the Internet Protocol defined an IP address as a 32-bit number[1] and this system, known as Internet Protocol Version 4 (IPv4), is still in use today. However, due to the enormous growth of the Internet and the predicted depletion of available addresses, a new addressing system (IPv6), using 128 bits for the address, was developed in 1995,[3] standardized as RFC 2460 in 1998,[4] and is being deployed worldwide since the mid-2000s.
IP addresses are binary numbers, but they are usually stored in text files and displayed in human-readable notations, such as 172.16.254.1 (for IPv4), and 2001:db8:0:1234:0:567:8:1 (for IPv6).
The Internet Assigned Numbers Authority (IANA) manages the IP address space allocations globally and delegates five regional Internet registries (RIRs) to allocate IP address blocks to local Internet registries (Internet service providers) and other entities.
Contents show hidden text
1 IP versions
1.1 IP version 4 addresses
1.1.1 IPv4 subnetting
1.1.2 IPv4 private addresses
1.2 IPv4 address exhaustion
1.3 IP version 6 addresses
1.3.1 IPv6 private addresses
2 IP subnetworks
3 IP address assignment
3.1 Methods
3.2 Uses of dynamic addressing
3.2.1 Sticky dynamic IP address
3.3 Address autoconfiguration
3.4 Uses of static addressing
4 Public addresses
5 Modifications to IP addressing
5.1 IP blocking and firewalls
5.2 IP address translation
6 Diagnostic tools
7 See also
8 References
9 External links
IP versions
Two versions of the Internet Protocol (IP) are in use: IP Version 4 and IP Version 6. Each version defines an IP address differently. Because of its prevalence, the generic term IP address typically still refers to the addresses defined by IPv4. The gap in version sequence between IPv4 and IPv6 resulted from the assignment of number 5 to the experimental Internet Stream Protocol in 1979, which however was never referred to as IPv5.
IP version 4 addresses
Main article: IPv4#Addressing
Decomposition of an IPv4 address from dot-decimal notation to its binary value.
In IPv4 an address consists of 32 bits which limits the address space to 4294967296 (232) possible unique addresses. IPv4 reserves some addresses for special purposes such as private networks (~18 million addresses) or multicast addresses (~270 million addresses).
IPv4 addresses are canonically represented in dot-decimal notation, which consists of four decimal numbers, each ranging from 0 to 255, separated by dots, e.g., 172.16.254.1. Each part represents a group of 8 bits (octet) of the address. In some cases of technical writing, IPv4 addresses may be presented in various hexadecimal, octal, or binary representations.
IPv4 subnetting
In the early stages of development of the Internet Protocol,[1] network administrators interpreted an IP address in two parts: network number portion and host number portion. The highest order octet (most significant eight bits) in an address was designated as the network number and the remaining bits were called the rest field or host identifier and were used for host numbering within a network.
This early method soon proved inadequate as additional networks developed that were independent of the existing networks already designated by a network number. In 1981, the Internet addressing specification was revised with the introduction of classful network architecture.[2]
Classful network design allowed for a larger number of individual network assignments and fine-grained subnetwork design. The first three bits of the most significant octet of an IP address were defined as the class of the address. Three classes (A, B, and C) were defined for universal unicast addressing. Depending on the class derived, the network identification was based on octet boundary segments of the entire address. Each class used successively additional octets in the network identifier, thus reducing the possible number of hosts in the higher order classes (B and C). The following table gives an overview of this now obsolete system.
Historical classful network architecture Class Leading
address bits Range of
first octet Network ID
format Host ID
format Number of networks Number of addresses
A 0 0 - 127 a b.c.d 27 = 128 224 = 16777216
B 10 128 - 191 a.b c.d 214 = 16384 216 = 65536
C 110 192 - 223 a.b.c d 221 = 2097152 28 = 256
Classful network design served its purpose in the startup stage of the Internet, but it lacked scalability in the face of the rapid expansion of the network in the 1990s. The class system of the address space was replaced with Classless Inter-Domain Routing (CIDR) in 1993. CIDR is based on variable-length subnet masking (VLSM) to allow allocation and routing based on arbitrary-length prefixes.
Today, remnants of classful network concepts function only in a limited scope as the default configuration parameters of some network software and hardware components (e.g. netmask), and in the technical jargon used in network administrators' discussions.
IPv4 private addresses
Early network design, when global end-to-end connectivity was envisioned for communications with all Internet hosts, intended that IP addresses be uniquely assigned to a particular computer or device. However, it was found that this was not always necessary as private networks developed and public address space needed to be conserved.
Computers not connected to the Internet, such as factory machines that communicate only with each other via TCP/IP, need not have globally unique IP addresses. Three ranges of IPv4 addresses for private networks were reserved in RFC 1918. These addresses are not routed on the Internet and thus their use need not be coordinated with an IP address registry.
Today, when needed, such private networks typically connect to the Internet through network address translation (NAT).
IANA-reserved private IPv4 network ranges Start End No. of addresses
24-bit Block (/8 prefix, 1 × A) 10.0.0.0 10.255.255.255 16777216
20-bit Block (/12 prefix, 16 × B) 172.16.0.0 172.31.255.255 1048576
16-bit Block (/16 prefix, 256 × C) 192.168.0.0 192.168.255.255 65536
Any user may use any of the reserved blocks. Typically, a network administrator will divide a block into subnets; for example, many home routers automatically use a default address range of 192.168.0.0 - 192.168.0.255 (192.168.0.0/24).
IPv4 address exhaustion
IPv4 address exhaustion is the decreasing supply of unallocated Internet Protocol Version 4 (IPv4) addresses available at the Internet Assigned Numbers Authority (IANA) and the regional Internet registries (RIRs) for assignment to end users and local Internet registries, such as Internet service providers. IANA's primary address pool was exhausted on February 3, 2011 when the last 5 blocks were allocated to the 5 RIRs.[5][6] APNIC was the first RIR to exhaust its regional pool on 15 April 2011, except for a small amount of address space reserved for the transition to IPv6, intended be allocated in a restricted process[7]
IP version 6 addresses
Main article: IPv6 address
Decomposition of an IPv6 address from hexadecimal representation to its binary value.
The rapid exhaustion of IPv4 address space, despite conservation techniques, prompted the Internet Engineering Task Force (IETF) to explore new technologies to expand the Internet's addressing capability. The permanent solution was deemed to be a redesign of the Internet Protocol itself. This next generation of the Internet Protocol, intended to replace IPv4 on the Internet, was eventually named Internet Protocol Version 6 (IPv6) in 1995[3][4] The address size was increased from 32 to 128 bits or 16 octets. This, even with a generous assignment of network blocks, is deemed sufficient for the foreseeable future. Mathematically, the new address space provides the potential for a maximum of 2128, or about 3.403×1038 unique addresses.
The new design is not intended to provide a sufficient quantity of addresses on its own, but rather to allow efficient aggregation of subnet routing prefixes to occur at routing nodes. As a result, routing table sizes are smaller, and the smallest possible individual allocation is a subnet for 264 hosts, which is the square of the size of the entire IPv4 Internet. At these levels, actual address utilization rates will be small on any IPv6 network segment. The new design also provides the opportunity to separate the addressing infrastructure of a network segment — that is the local administration of the segment's available space — from the addressing prefix used to route external traffic for a network. IPv6 has facilities that automatically change the routing prefix of entire networks, should the global connectivity or the routing policy change, without requiring internal redesign or renumbering.
The large number of IPv6 addresses allows large blocks to be assigned for specific purposes and, where appropriate, to be aggregated for efficient routing. With a large address space, there is not the need to have complex address conservation methods as used in Classless Inter-Domain Routing (CIDR).
Many modern desktop and enterprise server operating systems include native support for the IPv6 protocol, but it is not yet widely deployed in other devices, such as home networking routers, voice over IP (VoIP) and multimedia equipment, and network peripherals.
IPv6 private addresses
Just as IPv4 reserves addresses for private or internal networks, blocks of addresses are set aside in IPv6 for private addresses. In IPv6, these are referred to as unique local addresses (ULA). RFC 4193 sets aside the routing prefix fc00::/7 for this block which is divided into two /8 blocks with different implied policies The addresses include a 40-bit pseudorandom number that minimizes the risk of address collisions if sites merge or packets are misrouted.[8]
Early designs used a different block for this purpose (fec0::), dubbed site-local addresses.[9] However, the definition of what constituted sites remained unclear and the poorly defined addressing policy created ambiguities for routing. This address range specification was abandoned and must not be used in new systems.[10]
Addresses starting with fe80:, called link-local addresses, are assigned to interfaces for communication on the link only. The addresses are automatically generated by the operating system for each network interface. This provides instant and automatic network connectivity for any IPv6 host and means that if several hosts connect to a common hub or switch, they have a communication path via their link-local IPv6 address. This feature is used in the lower layers of IPv6 network administration (e.g. Neighbor Discovery Protocol).
None of the private address prefixes may be routed on the public Internet.
IP subnetworks
IP networks may be divided into subnetworks in both IPv4 and IPv6. For this purpose, an IP address is logically recognized as consisting of two parts: the network prefix and the host identifier, or interface identifier (IPv6). The subnet mask or the CIDR prefix determines how the IP address is divided into network and host parts.
The term subnet mask is only used within IPv4. Both IP versions however use the Classless Inter-Domain Routing (CIDR) concept and notation. In this, the IP address is followed by a slash and the number (in decimal) of bits used for the network part, also called the routing prefix. For example, an IPv4 address and its subnet mask may be 192.0.2.1 and 255.255.255.0, respectively. The CIDR notation for the same IP address and subnet is 192.0.2.1/24, because the first 24 bits of the IP address indicate the network and subnet.
IP address assignment
Internet Protocol addresses are assigned to a host either anew at the time of booting, or permanently by fixed configuration of its hardware or software. Persistent configuration is also known as using a static IP address. In contrast, in situations when the computer's IP address is assigned newly each time, this is known as using a dynamic IP address.
Methods
Static IP addresses are manually assigned to a computer by an administrator. The exact procedure varies according to platform. This contrasts with dynamic IP addresses, which are assigned either by the computer interface or host software itself, as in Zeroconf, or assigned by a server using Dynamic Host Configuration Protocol (DHCP). Even though IP addresses assigned using DHCP may stay the same for long periods of time, they can generally change. In some cases, a network administrator may implement dynamically assigned static IP addresses. In this case, a DHCP server is used, but it is specifically configured to always assign the same IP address to a particular computer. This allows static IP addresses to be configured centrally, without having to specifically configure each computer on the network in a manual procedure.
In the absence or failure of static or stateful (DHCP) address configurations, an operating system may assign an IP address to a network interface using state-less auto-configuration methods, such as Zeroconf.
Uses of dynamic addressing
Dynamic IP addresses are most frequently assigned on LANs and broadband networks by Dynamic Host Configuration Protocol (DHCP) servers. They are used because it avoids the administrative burden of assigning specific static addresses to each device on a network. It also allows many devices to share limited address space on a network if only some of them will be online at a particular time. In most current desktop operating systems, dynamic IP configuration is enabled by default so that a user does not need to manually enter any settings to connect to a network with a DHCP server. DHCP is not the only technology used to assign dynamic IP addresses. Dialup and some broadband networks use dynamic address features of the Point-to-Point Protocol.
Sticky dynamic IP address
A sticky dynamic IP address is an informal term used by cable and DSL Internet access subscribers to describe a dynamically assigned IP address that seldom changes. The addresses are usually assigned with the DHCP protocol. Since the modems are usually powered-on for extended periods of time, the address leases are usually set to long periods and simply renewed upon expiration. If a modem is turned off and powered up again before the next expiration of the address lease, it will most likely receive the same IP address.
Address autoconfiguration
RFC 3330 defines an address block, 169.254.0.0/16, for the special use in link-local addressing for IPv4 networks. In IPv6, every interface, whether using static or dynamic address assignments, also receives a local-link address automatically in the fe80::/10 subnet.
These addresses are only valid on the link, such as a local network segment or point-to-point connection, that a host is connected to. These addresses are not routable and like private addresses cannot be the source or destination of packets traversing the Internet.
When the link-local IPv4 address block was reserved, no standards existed for mechanisms of address autoconfiguration. Filling the void, Microsoft created an implementation that is called Automatic Private IP Addressing (APIPA). Due to Microsoft's market power, APIPA has been deployed on millions of machines and has, thus, become a de facto standard in the industry. Many years later, the IETF defined a formal standard for this functionality, RFC 3927, entitled Dynamic Configuration of IPv4 Link-Local Addresses.
Uses of static addressing
Some infrastructure situations have to use static addressing, such as when finding the Domain Name System (DNS) host that will translate domain names to IP addresses. Static addresses are also convenient, but not absolutely necessary, to locate servers inside an enterprise. An address obtained from a DNS server comes with a time to live, or caching time, after which it should be looked up to confirm that it has not changed. Even static IP addresses do change as a result of network administration (RFC 2072)
Public addresses
A public IP address in common parlance is synonymous with a, globally routable unicast IP address.[citation needed]
Both IPv4 and IPv6 define address ranges that are reserved for private networks and link-local addressing. The term public IP address often used exclude these types of addresses.
Modifications to IP addressing
IP blocking and firewalls
Firewalls perform Internet Protocol blocking to protect networks from unauthorized access. They are common on today's Internet. They control access to networks based on the IP address of a client computer. Whether using a blacklist or a whitelist, the IP address that is blocked is the perceived IP address of the client, meaning that if the client is using a proxy server or network address translation, blocking one IP address may block many individual computers.
IP address translation
Multiple client devices can appear to share IP addresses: either because they are part of a shared hosting web server environment or because an IPv4 network address translator (NAT) or proxy server acts as an intermediary agent on behalf of its customers, in which case the real originating IP addresses might be hidden from the server receiving a request. A common practice is to have a NAT hide a large number of IP addresses in a private network. Only the "outside" interface(s) of the NAT need to have Internet-routable addresses.[11]
Most commonly, the NAT device maps TCP or UDP port numbers on the outside to individual private addresses on the inside. Just as a telephone number may have site-specific extensions, the port numbers are site-specific extensions to an IP address.
In small home networks, NAT functions usually take place in a residential gateway device, typically one marketed as a "router". In this scenario, the computers connected to the router would have 'private' IP addresses and the router would have a 'public' address to communicate with the Internet. This type of router allows several computers to share one public IP address.
Diagnostic tools
Computer operating systems provide various diagnostic tools to examine their network interface and address configuration. Windows provides the command-line interface tools ipconfig and netsh and users of Unix-like systems can use ifconfig, netstat, route, lanstat, ifstat, or iproute2 utilities to accomplish the task.
See also
Address pool
Classful network
Geolocation
Geolocation software
Hierarchical name space
Hostname: a human-readable alpha-numeric designation that may map to an IP address
Internet service provider
IP address spoofing
IP blocking
IP Multicast
List of assigned /8 IPv4 address blocks
MAC address
Ping
Private network
Provider-aggregatable address space
Provider-independent address space
Regional Internet Registry
African Network Information Center
American Registry for Internet Numbers
Asia-Pacific Network Information Centre
Latin American and Caribbean Internet Addresses Registry
RIPE Network Coordination Centre
Subnet address
Virtual IP address
WHOIS
References
^ a b c RFC 760, DOD Standard Internet Protocol (January 1980)
^ a b RFC 791, Internet Protocol - DARPA Internet Program Protocol Specification (September 1981)
^ a b RFC 1883, Internet Protocol, Version 6 (IPv6) Specification, S. Deering, R. Hinden (December 1995)
^ a b RFC 2460, Internet Protocol, Version 6 (IPv6) Specification, S. Deering, R. Hinden, The Internet Society (December 1998)
^ Smith, Lucie; Lipner, Ian (3 February 2011). "Free Pool of IPv4 Address Space Depleted". Number Resource Organization. Retrieved 3 February 2011.
^ ICANN,nanog mailing list. "Five /8s allocated to RIRs - no unallocated IPv4 unicast /8s remain".
^ Asia-Pacific Network Information Centre (15 April 2011). "APNIC IPv4 Address Pool Reaches Final /8". Retrieved 15 April 2011.
^ RFC 4193 section 3.2.1
^ RFC 3513
^ RFC 3879
^ Comer, Douglas (2000). Internetworking with TCP/IP:Principles, Protocols, and Architectures -- 4th ed.. Upper Saddle River, NJ: Prentice Hall. p. 394. ISBN 0-13-018380-6.
External links
IP at the Open Directory Project
"Understanding IP Addressing: Everything You Ever Wanted To Know". Archived from the original on 2010-08-21.
Jump to: navigation, search
Page semi-protected
"Do not feed the trolls" and its abbreviation "DNFTT" redirect here. For the Wikimedia essay, see "What is a troll?".
The "trollface" sometimes used to indicate trolling.[1]
In Internet slang, a troll is someone who posts inflammatory[citation needed], extraneous, or off-topic messages in an online community, such as an online discussion forum, chat room, or blog, with the primary intent of provoking readers into an emotional response[2] or of otherwise disrupting normal on-topic discussion.[3] The noun troll may refer to the provocative message itself, as in: "That was an excellent troll you posted". While the word troll and its associated verb trolling are associated with Internet discourse, media attention in recent years has made such labels subjective, with trolling describing intentionally provocative actions outside of an online context. For example, mass media uses troll to describe "a person who defaces Internet tribute sites with the aim of causing grief to families."[4][5]
Contents
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* 1 Etymology
o 1.1 Early history
o 1.2 In other languages
* 2 Trolling, identity, and anonymity
* 3 Concern troll
* 4 Troll sites
* 5 Media coverage and controversy
* 6 Usage
* 7 Examples of trolling
* 8 See also
* 9 References
* 10 External links
Etymology
The verb troll originates from Old French troller, a hunting term. The noun troll comes from the Old Norse word for a mythological monster.[6]
In modern English usage, the verb troll is a fishing technique of slowly dragging a lure or baited hook from a moving boat.[7] The word evokes the trolls of Scandinavian folklore and children's tales, where they are often creatures bent on mischief and wickedness.
The contemporary use of the term is alleged to have appeared on the Internet in the late 1980s,[8] but the earliest known example is from 1992.[9] Early non-internet related use of trolling for actions deliberately performed to provoke a reaction can be found in the military; by 1972 the term trolling for MiGs was documented in use by US Navy pilots in Vietnam.[10]
Early history
The most likely derivation of the word troll can be found in the phrase "trolling for newbies", popularized in the early 1990s in the Usenet group, alt.folklore.urban (AFU).[11][12] Commonly, what is meant is a relatively gentle inside joke by veteran users, presenting questions or topics that had been so overdone that only a new user would respond to them earnestly. For example, a veteran of the group might make a post on the common misconception that glass flows over time. Long-time readers would both recognize the poster's name and know that the topic had been discussed a lot, but new subscribers to the group would not realize, and would thus respond. These types of trolls served as a practice to identify group insiders. This definition of trolling, considerably narrower than the modern understanding of the term, was considered a positive contribution.[11][13] One of the most notorious AFU trollers, Snopes,[11] went on to create his eponymous urban folklore website.
By the late 1990s, alt.folklore.urban had such heavy traffic and participation that trolling of this sort was frowned upon. Others expanded the term to include the practice of playing a seriously misinformed or deluded user, even in newsgroups where one was not a regular; these were often attempts at humor rather than provocation. In such contexts, the noun troll usually referred to an act of trolling, rather than to the author.
In other languages
In Icelandic, þurs (a thurs) or tröll (a troll) may refer to trolls, the verbs þursa (to troll) or þursast (to be trolling, to troll about) may used.
In Japanese, tsuri (つり) means "fishing" and refers to intentionally misleading posts whose only purpose is to get the readers to react, i.e. get trolled. arashi (あらし) means "laying waste" and can also be used to refer to simple spamming.
In Korean, nak-si (낚시) means "fishing", and is used to refer to Internet trolling attempts, as well as purposefully misleading post titles. A person who recognizes the troll after having responded (or, in case of a post title nak-si, having read the actual post) would often refer to himself as a caught fish.[citation needed]
In Thai, the term "krean" (เกรียน) has been adopted to address Internet trolls. The term literally refers to a closely cropped hairstyle worn by most school boys in Thailand, thus equating Internet trolls to school boys. The term "tob krean" (ตบเกรียน), or slapping a cropped head, refers to the act of posting intellectual replies to refute and cause the messages of Internet trolls to be unintelligent.[citation needed]
Trolling, identity, and anonymity
In academic literature, the practice of trolling was first documented by Judith Donath (1999). Donath's paper outlines the ambiguity of identity in a disembodied "virtual community" such as Usenet:
“ In the physical world there is an inherent unity to the self, for the body provides a compelling and convenient definition of identity. The norm is: one body, one identity ... The virtual world is different. It is composed of information rather than matter.[14] ”
Donath provides a concise overview of identity deception games which trade on the confusion between physical and epistemic community:
“ Trolling is a game about identity deception, albeit one that is played without the consent of most of the players. The troll attempts to pass as a legitimate participant, sharing the group's common interests and concerns; the newsgroups members, if they are cognizant of trolls and other identity deceptions, attempt to both distinguish real from trolling postings, and upon judging a poster a troll, make the offending poster leave the group. Their success at the former depends on how well they — and the troll — understand identity cues; their success at the latter depends on whether the troll's enjoyment is sufficiently diminished or outweighed by the costs imposed by the group.
Trolls can be costly in several ways. A troll can disrupt the discussion on a newsgroup, disseminate bad advice, and damage the feeling of trust in the newsgroup community. Furthermore, in a group that has become sensitized to trolling — where the rate of deception is high — many honestly naïve questions may be quickly rejected as trollings. This can be quite off-putting to the new user who upon venturing a first posting is immediately bombarded with angry accusations. Even if the accusation is unfounded, being branded a troll is quite damaging to one's online reputation.[14]
”
Susan Herring et al. in "Searching for Safety Online: Managing 'Trolling' in a Feminist Forum" point out the difficulty inherent in monitoring trolling and maintaining freedom of speech in online communities: "harassment often arises in spaces known for their freedom, lack of censure, and experimental nature".[15] Free speech may lead to tolerance of trolling behavior, complicating the members' efforts to maintain an open, yet supportive discussion area, especially for sensitive topics such as race, gender, and sexuality.[15]
In an effort to reduce uncivil behavior by increasing accountability, many web sites (e.g. Reuters, Facebook, and Gizmodo) now require commenters to register their names and e-mail addresses.[16]
Concern troll
A concern troll is a false flag pseudonym created by a user whose actual point of view is opposed to the one that the user claims to hold. The concern troll posts in Web forums devoted to its declared point of view and attempts to sway the group's actions or opinions while claiming to share their goals, but with professed "concerns". The goal is to sow fear, uncertainty and doubt within the group.[17]
An example of this occurred in 2006 when Tad Furtado, a staffer for then-Congressman Charles Bass (R-NH), was caught posing as a "concerned" supporter of Bass's opponent, Democrat Paul Hodes, on several liberal New Hampshire blogs, using the pseudonyms "IndieNH" or "IndyNH". "IndyNH" expressed concern that Democrats might just be wasting their time or money on Hodes, because Bass was unbeatable.[18][19]
Although the term "concern troll" originated in discussions of online behavior, it now sees increasing use to describe similar behaviors that take place offline.
For example, James Wolcott of Vanity Fair accused a conservative New York Daily News columnist of "concern troll" behavior in his efforts to downplay the Mark Foley scandal. Wolcott links what he calls concern trolls to Saul Alinsky's "Do-Nothings", giving a long quote from Alinsky on the Do-Nothings' method and effects:
“ These Do-Nothings profess a commitment to social change for ideals of justice, equality, and opportunity, and then abstain from and discourage all effective action for change. They are known by their brand, 'I agree with your ends but not your means.'[20] ”
The Hill published an op-ed piece by Markos Moulitsas of the liberal blog Daily Kos titled "Dems: Ignore 'Concern Trolls' ". The concern trolls in question were not Internet participants; they were Republicans offering public advice and warnings to the Democrats. The author defines "concern trolling" as "offering a poisoned apple in the form of advice to political opponents that, if taken, would harm the recipient".[21]
Troll sites
While many webmasters and forum administrators consider trolls a scourge on their sites, some websites welcome them. For example, a New York Times article discussed troll activity at 4chan and at Encyclopedia Dramatica, which it described as "an online compendium of troll humor and troll lore".[8] This site and others are often used as a base to troll against sites that their members can not normally post on. These trolls feed off the reactions of their victims because "their agenda is to take delight in causing trouble".[22]
Media coverage and controversy
Mainstream media outlets have focused their attention on the willingness of some Internet trolls to go to extreme lengths in their attempts at eliciting reactions.
On March 31, 2010, the Today Show ran a segment detailing the deaths of three separate adolescent girls and trolls’ subsequent reactions to their deaths. Shortly after the suicide of high school student Alexis Pilkington, anonymous posters began trolling for reactions across various message boards, referring to Pilkington as a “suicidal slut,” and posting graphic images on her Facebook memorial page. The segment also included an expose of a 2006 accident, in which an eighteen-year old fatally crashed her father’s car into a highway pylon; trolls emailed her grieving family the leaked pictures of her mutilated corpse.[5]
In February 2010, the Australian government became involved after trolls defaced the Facebook tribute pages of murdered children Trinity Bates and Elliott Fletcher. Australian communications minister Stephen Conroy decried the attacks, committed mainly by 4chan users, as evidence of the need for greater Internet regulation, stating, “This argument that the Internet is some mystical creation that no laws should apply to, that is a recipe for anarchy and the wild west.”[23] Conroy has been noted in the past for his advocacy of Internet censorship. In the wake of these events, Facebook responded by strongly urging administrators to be aware of ways to ban users and remove inappropriate content from Facebook pages.[24]
Usage
Application of the term troll is subjective. Some readers may characterize a post as trolling, while others may regard the same post as a legitimate contribution to the discussion, even if controversial. Like any pejorative term, it can be used as an ad hominem attack, suggesting a negative motivation.
Regardless of the circumstances, controversial posts may attract a particularly strong response from those unfamiliar with the robust dialogue found in some online, rather than physical, communities. Experienced participants in online forums know that the most effective way to discourage a troll is usually to ignore it, because responding tends to encourage trolls to continue disruptive posts — hence the often-seen warning: "Please do not feed the trolls".
Examples of trolling
A prank cake using common troll motifs such as the acronym "YHBT" (You Have Been Trolled), the term "pwned", and Guy Fawkes masks.
So-called Gold Membership trolling originated in 2007 on 4chan boards, users posting fake images claiming to offer upgraded 4chan account privileges; without a “Gold” account, one could not view certain content. This turned out to be a hoax designed to fool board members, especially newcomers. It was copied and became an Internet meme. In some cases, this type of troll has been used as a scam, most notably on Facebook, where fake Facebook Gold Account upgrade ads have proliferated in order to link users to dubious websites and other content.[25]
As reported on April 8, 1999, investors became victims of trolling via an online financial discussion regarding PairGain, a telephone equipment company based in California. Trolls operating in the stock’s Yahoo Finance chat room posted a fabricated Bloomberg News article stating that an Israeli telecom company could potentially acquire PairGain. As a result, PairGain’s stock jumped by 31%. However, the stock promptly crashed after the reports were identified as false.[26]
The case of Zeran v. America Online, Inc. resulted primarily from trolling. Six days after the Oklahoma City bombing, anonymous users posted advertisements for shirts celebrating the bombing on AOL message boards, claiming that the shirts could be obtained by contacting Mr. Kenneth Zeran. The posts listed Zeran’s address and home phone number. Zeran was subsequently harassed.[26]
Anti-Scientology protests by Anonymous, commonly known as Project Chanology, are sometimes labeled as "trolling" by media such as Wired,[27] and the participants sometimes explicitly self-identify as "trolls".
See also
Crystal Clear app browser.png Internet portal
* Anonymous (group)
* Anti-social behaviour
* Breaching experiment
* Cyber-bullying
* Flamewar
* Gay Nigger Association of America
* Griefer
* Heckler
* Hit-and-run posting
* Lurker
* Patent troll
* Patriotic Nigras
* Sockpuppet (Internet)
References
1. ^ Online 'Trolls' Target Family Tribute Pages. Sky News. Retrieved 15 April 2011.
2. ^ "Definition of: trolling". PCMAG.COM. Ziff Davis Publishing Holdings Inc. 2009. http://www.pcmag.com/encyclopedia_term/0,2542,t=trolling&i=53181,00.asp#. Retrieved 2009-03-24.
3. ^ Indiana University: University Information Technology Services (2008-05-05). "What is a troll?". Indiana University Knowledge Base. The Trustees of Indiana University. http://kb.iu.edu/data/afhc.html. Retrieved 2009-03-24.
4. ^ "Police charge alleged creator of Facebook hate page aimed at murder victim". The Courier Mail (Australia). 2010-07-22. http://www.couriermail.com.au/news/queensland/police-charge-alleged-creator-of-facebook-hate-page-aimed-at-murder-victim/story-e6freoof-1225895789100. Retrieved 2010-07-27.
5. ^ a b "Trolling: The Today Show Explores the Dark Side of the Internet", March 31, 2010. Retrieved on April 4, 2010.
6. ^ Harper, Douglas. "troll". Online Etymology Dictionary. http://www.etymonline.com/index.php?term=troll. Retrieved 2009-03-24.
7. ^ "troll". Merriam-Webster Online Dictionary. 2010. http://www.merriam-webster.com/dictionary/troll. Retrieved 7 January 2010.
8. ^ a b Schwartz, Mattathias (2008-08-03). "The Trolls Among Us". The New York Times: pp. MM24. http://www.nytimes.com/2008/08/03/magazine/03trolls-t.html. Retrieved 2009-03-24.
9. ^ troll, n.1. Oxford University Press. 2006. http://dictionary.oed.com/cgi/entry/50258589?query_type=word&queryword=Troll&first=1&max_to_show=10&sort_type=alpha&result_place=1&search_id=IQ9r-MltHmU-3840&hilite=50258589. Retrieved 1 March 2010. OED gives an example from alt.folklore.urban (Usenet newsgroup), 14 December 1992
10. ^ John Saar (February 4, 1972). "Carrier War". Life. http://books.google.com/books?id=EkAEAAAAMBAJ&pg=PA28.
11. ^ a b c Tepper, Michele (1997). "Usenet Communities and the Cultural Politics of Information". In Porter, David. Internet culture. New York, New York, United States: Routledge Inc. p. 48. ISBN 9780415916837. http://books.google.com/?id=5d2stzIbkqMC. Retrieved 2009-03-24. "... the two most notorious trollers in AFU, Ted Frank and Snopes, are also two of the most consistent posters of serious research."
12. ^ Miller, Mark S. (1990-02-08). "FOADTAD". alt.flame. (Web link). Retrieved 2009-06-02. "Just go die in your sleep you mindless flatulent troll."
13. ^ Zotti, Ed; et al. (2000-04-14). "What is a troll?". The Straight Dope. http://www.straightdope.com/columns/read/1764/what-is-a-troll. Retrieved 2009-03-24. "To be fair, not all trolls are slimeballs. On some message boards, veteran posters with a mischievous bent occasionally go 'newbie trolling.'"
14. ^ a b Donath, Judith S. (1999). "Identity and deception in the virtual community". In Smith, Marc A.; Kollock, Peter. Communities in Cyberspace (illustrated, reprint ed.). Routledge. pp. 29–59. ISBN 9780415191401. http://books.google.com/?id=210IkjyN8gEC. Retrieved 2009-03-24.
15. ^ a b Herring, Susan; Job-Sluder, Kirk; Scheckler, Rebecca; Barab, Sasha (2002). "Searching for Safety Online: Managing "Trolling" in a Feminist Forum". Center for Social Informatics — Indiana University. http://rkcsi.indiana.edu/archive/CSI/WP/WP02-03B.html. Retrieved 2009-03-29.
16. ^ J. Zhao, Where Anonymity Breeds Contempt, NY Times, 29 Nov 2010.
17. ^ Cox, Ana Marie (2006-12-16). "Making Mischief on the Web". TIME. http://www.time.com/time/magazine/article/0,9171,1570701,00.html. Retrieved 2009-03-24.
18. ^ Saunders, Anne (2006-09-27). "Bass aide resigns for fake website postings". Associated Press. http://www.concordmonitor.com/apps/pbcs.dll/article?AID=/20060927/REPOSITORY/609270353. Retrieved 2010-02-05.
19. ^ "Bass Aide Resigns After Posing As Democrat On Blogs". 2006-09-26. http://www.wmur.com/politics/9936715/detail.html. Retrieved 2010-02-05.
20. ^ Wolcott, James (2006-10-06). "Political Pieties from a Post-Natal Drip". James Wolcott's Blog — Vanity Fair. Condé Nast. http://www.vanityfair.com/online/wolcott/2006/10/political_pieti.html. Retrieved 2009-03-25.
21. ^ Moulitsas, Markos (2008-01-09). "Dems: Ignore 'concern trolls'". TheHill.com. Capitol Hill Publishing Corp. http://thehill.com/opinion/columnists/markos-moulitas/24407-dems-ignore-concern-trolls. Retrieved 2009-03-25.
22. ^ "How to be a Great Internet Troll". Fox Sports. http://community.foxsports.com/dwilliams/blog/2007/10/25/how_to_be_a_great_internet_troll. Retrieved 2009-12-13.
23. ^ "Internet without laws a 'recipe for anarchy', 1 April 2010. Retrieved 5 April 2010.
24. ^ "Facebook takes (small) step against tribute page trolls", TG Daily, 30 March 2010. Retrieved 5 April 2010.
25. ^ "All that glisters is not (Facebook) gold", CounterMeasures: Security, Privacy & Trust (A TrendMicro Blog). Retrieved 6 April 2010.
26. ^ a b Bond, Robert (1999). "Links, Frames, Meta-tags and Trolls". International Review of Law, Computers & Technology 13: pp. 317–323.
27. ^ Dibbell, Julian (September 21, 2009). "The Assclown Offensive: How to Enrage the Church of Scientology". Wired. http://www.wired.com/culture/culturereviews/magazine/17-10/mf_chanology. Retrieved October 5, 2010.
External links
Look up troll in Wiktionary, the free dictionary.
Wikimedia Commons has media related to: Trolls (Internet)
Wikinews has related news: UK court jails man for trolling online tribute pages
* Usenet and Bulletin Board Abuse at the Open Directory Project
* Article on trolls and the 'art' of trolling by Steve Myers
* What is a troll? from the Straight Dope
* Trolling lore and essays
* Searching for Safety Online: Managing "Trolling" in a Feminist Forum
* Malwebolence – The World of Web Trolling; New York Times Magazine, By Mattathias Schwartz; August 3, 2008.
* The relationship between social context cues and uninhibited verbal behavior in computer-mediated communication
* The Subtle Art of Trolling
* A Discussion on Flaming from New Scientist Technology Blog
For the Wikipedia user access level, see Wikipedia:User access levels#Unregistered_users.
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An Internet Protocol address (IP address) is a numerical label assigned to each device (e.g., computer, printer) participating in a computer network that uses the Internet Protocol for communication.[1] An IP address serves two principal functions: host or network interface identification and location addressing. Its role has been characterized as follows: "A name indicates what we seek. An address indicates where it is. A route indicates how to get there."[2]
The designers of the Internet Protocol defined an IP address as a 32-bit number[1] and this system, known as Internet Protocol Version 4 (IPv4), is still in use today. However, due to the enormous growth of the Internet and the predicted depletion of available addresses, a new addressing system (IPv6), using 128 bits for the address, was developed in 1995,[3] standardized as RFC 2460 in 1998,[4] and is being deployed worldwide since the mid-2000s.
IP addresses are binary numbers, but they are usually stored in text files and displayed in human-readable notations, such as 172.16.254.1 (for IPv4), and 2001:db8:0:1234:0:567:8:1 (for IPv6).
The Internet Assigned Numbers Authority (IANA) manages the IP address space allocations globally and delegates five regional Internet registries (RIRs) to allocate IP address blocks to local Internet registries (Internet service providers) and other entities.
Contents
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1 IP versions
1.1 IP version 4 addresses
1.1.1 IPv4 subnetting
1.1.2 IPv4 private addresses
1.2 IPv4 address exhaustion
1.3 IP version 6 addresses
1.3.1 IPv6 private addresses
2 IP subnetworks
3 IP address assignment
3.1 Methods
3.2 Uses of dynamic addressing
3.2.1 Sticky dynamic IP address
3.3 Address autoconfiguration
3.4 Uses of static addressing
4 Public addresses
5 Modifications to IP addressing
5.1 IP blocking and firewalls
5.2 IP address translation
6 Diagnostic tools
7 See also
8 References
9 External links
IP versions
Two versions of the Internet Protocol (IP) are in use: IP Version 4 and IP Version 6. Each version defines an IP address differently. Because of its prevalence, the generic term IP address typically still refers to the addresses defined by IPv4. The gap in version sequence between IPv4 and IPv6 resulted from the assignment of number 5 to the experimental Internet Stream Protocol in 1979, which however was never referred to as IPv5.
IP version 4 addresses
Main article: IPv4#Addressing
Decomposition of an IPv4 address from dot-decimal notation to its binary value.
In IPv4 an address consists of 32 bits which limits the address space to 4294967296 (232) possible unique addresses. IPv4 reserves some addresses for special purposes such as private networks (~18 million addresses) or multicast addresses (~270 million addresses).
IPv4 addresses are canonically represented in dot-decimal notation, which consists of four decimal numbers, each ranging from 0 to 255, separated by dots, e.g., 172.16.254.1. Each part represents a group of 8 bits (octet) of the address. In some cases of technical writing, IPv4 addresses may be presented in various hexadecimal, octal, or binary representations.
IPv4 subnetting
In the early stages of development of the Internet Protocol,[1] network administrators interpreted an IP address in two parts: network number portion and host number portion. The highest order octet (most significant eight bits) in an address was designated as the network number and the remaining bits were called the rest field or host identifier and were used for host numbering within a network.
This early method soon proved inadequate as additional networks developed that were independent of the existing networks already designated by a network number. In 1981, the Internet addressing specification was revised with the introduction of classful network architecture.[2]
Classful network design allowed for a larger number of individual network assignments and fine-grained subnetwork design. The first three bits of the most significant octet of an IP address were defined as the class of the address. Three classes (A, B, and C) were defined for universal unicast addressing. Depending on the class derived, the network identification was based on octet boundary segments of the entire address. Each class used successively additional octets in the network identifier, thus reducing the possible number of hosts in the higher order classes (B and C). The following table gives an overview of this now obsolete system.
Historical classful network architecture Class Leading
address bits Range of
first octet Network ID
format Host ID
format Number of networks Number of addresses
A 0 0 - 127 a b.c.d 27 = 128 224 = 16777216
B 10 128 - 191 a.b c.d 214 = 16384 216 = 65536
C 110 192 - 223 a.b.c d 221 = 2097152 28 = 256
Classful network design served its purpose in the startup stage of the Internet, but it lacked scalability in the face of the rapid expansion of the network in the 1990s. The class system of the address space was replaced with Classless Inter-Domain Routing (CIDR) in 1993. CIDR is based on variable-length subnet masking (VLSM) to allow allocation and routing based on arbitrary-length prefixes.
Today, remnants of classful network concepts function only in a limited scope as the default configuration parameters of some network software and hardware components (e.g. netmask), and in the technical jargon used in network administrators' discussions.
IPv4 private addresses
Early network design, when global end-to-end connectivity was envisioned for communications with all Internet hosts, intended that IP addresses be uniquely assigned to a particular computer or device. However, it was found that this was not always necessary as private networks developed and public address space needed to be conserved.
Computers not connected to the Internet, such as factory machines that communicate only with each other via TCP/IP, need not have globally unique IP addresses. Three ranges of IPv4 addresses for private networks were reserved in RFC 1918. These addresses are not routed on the Internet and thus their use need not be coordinated with an IP address registry.
Today, when needed, such private networks typically connect to the Internet through network address translation (NAT).
IANA-reserved private IPv4 network ranges Start End No. of addresses
24-bit Block (/8 prefix, 1 × A) 10.0.0.0 10.255.255.255 16777216
20-bit Block (/12 prefix, 16 × B) 172.16.0.0 172.31.255.255 1048576
16-bit Block (/16 prefix, 256 × C) 192.168.0.0 192.168.255.255 65536
Any user may use any of the reserved blocks. Typically, a network administrator will divide a block into subnets; for example, many home routers automatically use a default address range of 192.168.0.0 - 192.168.0.255 (192.168.0.0/24).
IPv4 address exhaustion
IPv4 address exhaustion is the decreasing supply of unallocated Internet Protocol Version 4 (IPv4) addresses available at the Internet Assigned Numbers Authority (IANA) and the regional Internet registries (RIRs) for assignment to end users and local Internet registries, such as Internet service providers. IANA's primary address pool was exhausted on February 3, 2011 when the last 5 blocks were allocated to the 5 RIRs.[5][6] APNIC was the first RIR to exhaust its regional pool on 15 April 2011, except for a small amount of address space reserved for the transition to IPv6, intended be allocated in a restricted process[7]
IP version 6 addresses
Main article: IPv6 address
Decomposition of an IPv6 address from hexadecimal representation to its binary value.
The rapid exhaustion of IPv4 address space, despite conservation techniques, prompted the Internet Engineering Task Force (IETF) to explore new technologies to expand the Internet's addressing capability. The permanent solution was deemed to be a redesign of the Internet Protocol itself. This next generation of the Internet Protocol, intended to replace IPv4 on the Internet, was eventually named Internet Protocol Version 6 (IPv6) in 1995[3][4] The address size was increased from 32 to 128 bits or 16 octets. This, even with a generous assignment of network blocks, is deemed sufficient for the foreseeable future. Mathematically, the new address space provides the potential for a maximum of 2128, or about 3.403×1038 unique addresses.
The new design is not intended to provide a sufficient quantity of addresses on its own, but rather to allow efficient aggregation of subnet routing prefixes to occur at routing nodes. As a result, routing table sizes are smaller, and the smallest possible individual allocation is a subnet for 264 hosts, which is the square of the size of the entire IPv4 Internet. At these levels, actual address utilization rates will be small on any IPv6 network segment. The new design also provides the opportunity to separate the addressing infrastructure of a network segment — that is the local administration of the segment's available space — from the addressing prefix used to route external traffic for a network. IPv6 has facilities that automatically change the routing prefix of entire networks, should the global connectivity or the routing policy change, without requiring internal redesign or renumbering.
The large number of IPv6 addresses allows large blocks to be assigned for specific purposes and, where appropriate, to be aggregated for efficient routing. With a large address space, there is not the need to have complex address conservation methods as used in Classless Inter-Domain Routing (CIDR).
Many modern desktop and enterprise server operating systems include native support for the IPv6 protocol, but it is not yet widely deployed in other devices, such as home networking routers, voice over IP (VoIP) and multimedia equipment, and network peripherals.
IPv6 private addresses
Just as IPv4 reserves addresses for private or internal networks, blocks of addresses are set aside in IPv6 for private addresses. In IPv6, these are referred to as unique local addresses (ULA). RFC 4193 sets aside the routing prefix fc00::/7 for this block which is divided into two /8 blocks with different implied policies The addresses include a 40-bit pseudorandom number that minimizes the risk of address collisions if sites merge or packets are misrouted.[8]
Early designs used a different block for this purpose (fec0::), dubbed site-local addresses.[9] However, the definition of what constituted sites remained unclear and the poorly defined addressing policy created ambiguities for routing. This address range specification was abandoned and must not be used in new systems.[10]
Addresses starting with fe80:, called link-local addresses, are assigned to interfaces for communication on the link only. The addresses are automatically generated by the operating system for each network interface. This provides instant and automatic network connectivity for any IPv6 host and means that if several hosts connect to a common hub or switch, they have a communication path via their link-local IPv6 address. This feature is used in the lower layers of IPv6 network administration (e.g. Neighbor Discovery Protocol).
None of the private address prefixes may be routed on the public Internet.
IP subnetworks
IP networks may be divided into subnetworks in both IPv4 and IPv6. For this purpose, an IP address is logically recognized as consisting of two parts: the network prefix and the host identifier, or interface identifier (IPv6). The subnet mask or the CIDR prefix determines how the IP address is divided into network and host parts.
The term subnet mask is only used within IPv4. Both IP versions however use the Classless Inter-Domain Routing (CIDR) concept and notation. In this, the IP address is followed by a slash and the number (in decimal) of bits used for the network part, also called the routing prefix. For example, an IPv4 address and its subnet mask may be 192.0.2.1 and 255.255.255.0, respectively. The CIDR notation for the same IP address and subnet is 192.0.2.1/24, because the first 24 bits of the IP address indicate the network and subnet.
IP address assignment
Internet Protocol addresses are assigned to a host either anew at the time of booting, or permanently by fixed configuration of its hardware or software. Persistent configuration is also known as using a static IP address. In contrast, in situations when the computer's IP address is assigned newly each time, this is known as using a dynamic IP address.
Methods
Static IP addresses are manually assigned to a computer by an administrator. The exact procedure varies according to platform. This contrasts with dynamic IP addresses, which are assigned either by the computer interface or host software itself, as in Zeroconf, or assigned by a server using Dynamic Host Configuration Protocol (DHCP). Even though IP addresses assigned using DHCP may stay the same for long periods of time, they can generally change. In some cases, a network administrator may implement dynamically assigned static IP addresses. In this case, a DHCP server is used, but it is specifically configured to always assign the same IP address to a particular computer. This allows static IP addresses to be configured centrally, without having to specifically configure each computer on the network in a manual procedure.
In the absence or failure of static or stateful (DHCP) address configurations, an operating system may assign an IP address to a network interface using state-less auto-configuration methods, such as Zeroconf.
Uses of dynamic addressing
Dynamic IP addresses are most frequently assigned on LANs and broadband networks by Dynamic Host Configuration Protocol (DHCP) servers. They are used because it avoids the administrative burden of assigning specific static addresses to each device on a network. It also allows many devices to share limited address space on a network if only some of them will be online at a particular time. In most current desktop operating systems, dynamic IP configuration is enabled by default so that a user does not need to manually enter any settings to connect to a network with a DHCP server. DHCP is not the only technology used to assign dynamic IP addresses. Dialup and some broadband networks use dynamic address features of the Point-to-Point Protocol.
Sticky dynamic IP address
A sticky dynamic IP address is an informal term used by cable and DSL Internet access subscribers to describe a dynamically assigned IP address that seldom changes. The addresses are usually assigned with the DHCP protocol. Since the modems are usually powered-on for extended periods of time, the address leases are usually set to long periods and simply renewed upon expiration. If a modem is turned off and powered up again before the next expiration of the address lease, it will most likely receive the same IP address.
Address autoconfiguration
RFC 3330 defines an address block, 169.254.0.0/16, for the special use in link-local addressing for IPv4 networks. In IPv6, every interface, whether using static or dynamic address assignments, also receives a local-link address automatically in the fe80::/10 subnet.
These addresses are only valid on the link, such as a local network segment or point-to-point connection, that a host is connected to. These addresses are not routable and like private addresses cannot be the source or destination of packets traversing the Internet.
When the link-local IPv4 address block was reserved, no standards existed for mechanisms of address autoconfiguration. Filling the void, Microsoft created an implementation that is called Automatic Private IP Addressing (APIPA). Due to Microsoft's market power, APIPA has been deployed on millions of machines and has, thus, become a de facto standard in the industry. Many years later, the IETF defined a formal standard for this functionality, RFC 3927, entitled Dynamic Configuration of IPv4 Link-Local Addresses.
Uses of static addressing
Some infrastructure situations have to use static addressing, such as when finding the Domain Name System (DNS) host that will translate domain names to IP addresses. Static addresses are also convenient, but not absolutely necessary, to locate servers inside an enterprise. An address obtained from a DNS server comes with a time to live, or caching time, after which it should be looked up to confirm that it has not changed. Even static IP addresses do change as a result of network administration (RFC 2072)
Public addresses
A public IP address in common parlance is synonymous with a, globally routable unicast IP address.[citation needed]
Both IPv4 and IPv6 define address ranges that are reserved for private networks and link-local addressing. The term public IP address often used exclude these types of addresses.
Modifications to IP addressing
IP blocking and firewalls
Firewalls perform Internet Protocol blocking to protect networks from unauthorized access. They are common on today's Internet. They control access to networks based on the IP address of a client computer. Whether using a blacklist or a whitelist, the IP address that is blocked is the perceived IP address of the client, meaning that if the client is using a proxy server or network address translation, blocking one IP address may block many individual computers.
IP address translation
Multiple client devices can appear to share IP addresses: either because they are part of a shared hosting web server environment or because an IPv4 network address translator (NAT) or proxy server acts as an intermediary agent on behalf of its customers, in which case the real originating IP addresses might be hidden from the server receiving a request. A common practice is to have a NAT hide a large number of IP addresses in a private network. Only the "outside" interface(s) of the NAT need to have Internet-routable addresses.[11]
Most commonly, the NAT device maps TCP or UDP port numbers on the outside to individual private addresses on the inside. Just as a telephone number may have site-specific extensions, the port numbers are site-specific extensions to an IP address.
In small home networks, NAT functions usually take place in a residential gateway device, typically one marketed as a "router". In this scenario, the computers connected to the router would have 'private' IP addresses and the router would have a 'public' address to communicate with the Internet. This type of router allows several computers to share one public IP address.
Diagnostic tools
Computer operating systems provide various diagnostic tools to examine their network interface and address configuration. Windows provides the command-line interface tools ipconfig and netsh and users of Unix-like systems can use ifconfig, netstat, route, lanstat, ifstat, or iproute2 utilities to accomplish the task.
See also
Address pool
Classful network
Geolocation
Geolocation software
Hierarchical name space
Hostname: a human-readable alpha-numeric designation that may map to an IP address
Internet service provider
IP address spoofing
IP blocking
IP Multicast
List of assigned /8 IPv4 address blocks
MAC address
Ping
Private network
Provider-aggregatable address space
Provider-independent address space
Regional Internet Registry
African Network Information Center
American Registry for Internet Numbers
Asia-Pacific Network Information Centre
Latin American and Caribbean Internet Addresses Registry
RIPE Network Coordination Centre
Subnet address
Virtual IP address
WHOIS
References
^ a b c RFC 760, DOD Standard Internet Protocol (January 1980)
^ a b RFC 791, Internet Protocol - DARPA Internet Program Protocol Specification (September 1981)
^ a b RFC 1883, Internet Protocol, Version 6 (IPv6) Specification, S. Deering, R. Hinden (December 1995)
^ a b RFC 2460, Internet Protocol, Version 6 (IPv6) Specification, S. Deering, R. Hinden, The Internet Society (December 1998)
^ Smith, Lucie; Lipner, Ian (3 February 2011). "Free Pool of IPv4 Address Space Depleted". Number Resource Organization. Retrieved 3 February 2011.
^ ICANN,nanog mailing list. "Five /8s allocated to RIRs - no unallocated IPv4 unicast /8s remain".
^ Asia-Pacific Network Information Centre (15 April 2011). "APNIC IPv4 Address Pool Reaches Final /8". Retrieved 15 April 2011.
^ RFC 4193 section 3.2.1
^ RFC 3513
^ RFC 3879
^ Comer, Douglas (2000). Internetworking with TCP/IP:Principles, Protocols, and Architectures -- 4th ed.. Upper Saddle River, NJ: Prentice Hall. p. 394. ISBN 0-13-018380-6.
External links
IP at the Open Directory Project
"Understanding IP Addressing: Everything You Ever Wanted To Know". Archived from the original on 2010-08-21.