computer network A computer network is a set of computers sharing resources located on or provided by network nodes. The computers use common communication protocols over digital interconnections to communicate with each other. These interconnections ar ...

ing, the Name/Finger protocol and the Finger user information protocol are simple

network protocols A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. The protocol defines the rules, syntax, semantics and synchroni ...

for the exchange of human-oriented status and user information.

Name/Finger protocol

The Name/Finger protocol is based on

Request for Comments A Request for Comments (RFC) is a publication in a series from the principal technical development and standards-setting bodies for the Internet, most prominently the Internet Engineering Task Force (IETF). An RFC is authored by individuals or ...

document (December 1977) as an interface to the name and finger programs that provide status reports on a particular computer system or a particular person at network sites. The finger program was written in 1971 by

Les Earnest Lester Donald Earnest (born December 17, 1930) is an American computer scientist. Education and career After receiving his B.S. in electrical engineering from the California Institute of Technology (Caltech) in 1953, he began his career as a co ...

who created the program to solve the need of users who wanted information on other users of the network. Information on who is logged in was useful to check the availability of a person to meet. This was probably the earliest form of

presence information In computer and telecommunications networks, presence information is a status indicator that conveys ability and willingness of a potential communication partner—for example a user—to communicate. A user's client provides presence information (p ...

for remote network users. Prior to the finger program, the only way to get this information was with a who program that showed IDs and terminal line numbers (the server's internal number of the communication line, over which the user's terminal is connected) for logged-in users. Earnest named his program after the idea that people would run their fingers down the who list to find what they were looking for. The term "finger" has a definition of "to snitch" or "to identify": this made "finger" a good reminder/mnemonic to the semantic of the

UNIX Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...

finger command (a ''client'' in the protocol context).

Finger user information protocol

The finger

daemon Daimon or Daemon (Ancient Greek: , "god", "godlike", "power", "fate") originally referred to a lesser deity or guiding spirit such as the daimons of ancient Greek religion and mythology and of later Hellenistic religion and philosophy. The wo ...

runs on TCP port 79. The client will (in the case of remote hosts) open a connection to port 79. An RUIP (Remote User Information Program) is started on the remote end of the connection to process the request. The local host sends the RUIP one line query based upon the Finger query specification, and waits for the RUIP to respond. The RUIP receives and processes the query, returns an answer, then initiates the close of the connection. The local host receives the answer and the close signal, then proceeds to close its end of the connection. The Finger user information protocol is based on (''The Finger User Information Protocol'', December 1991). Typically the server side of the protocol is implemented by a program fingerd or in.fingerd (for ''finger

''), while the

client Client(s) or The Client may refer to: * Client (business) * Client (computing), hardware or software that accesses a remote service on another computer * Customer or client, a recipient of goods or services in return for monetary or other valuabl ...

side is implemented by the name and finger programs which are supposed to return a friendly, human-oriented status report on either the system at the moment or a particular person in depth. There is no required format, and the protocol consists mostly of specifying a single

command line A command-line interpreter or command-line processor uses a command-line interface (CLI) to receive commands from a user in the form of lines of text. This provides a means of setting parameters for the environment, invoking executables and pro ...

. The program would supply information such as whether a user is currently logged-on,

e-mail address An email address identifies an email box to which messages are delivered. While early messaging systems used a variety of formats for addressing, today, email addresses follow a set of specific rules originally standardized by the Internet Engine ...

, full name etc. As well as standard user information, finger displays the contents of the .project and .plan files in the user's

home directory A home directory is a file system directory on a multi-user operating system containing files for a given user of the system. The specifics of the home directory (such as its name and location) are defined by the operating system involved; for ...

. Often this file (maintained by the user) contains either useful information about the user's current activities, similar to

micro-blogging Microblogging is a form of social network that permits only short posts. They "allow users to exchange small elements of content such as short sentences, individual images, or video links",. Retrieved June 5, 2014 which may be the major reason for ...

, or alternatively all manner of humor.

Security concerns

Supplying such detailed information as e-mail addresses and full names was considered acceptable and convenient in the early days of networking, but later was considered questionable for privacy and security reasons. Finger information has been used by

hacker A hacker is a person skilled in information technology who uses their technical knowledge to achieve a goal or overcome an obstacle, within a computerized system by non-standard means. Though the term ''hacker'' has become associated in popu ...

s as a way to initiate a

social engineering Social engineering may refer to: * Social engineering (political science), a means of influencing particular attitudes and social behaviors on a large scale * Social engineering (security), obtaining confidential information by manipulating and/or ...

attack on a company's computer security system. By using a finger client to get a list of a company's employee names, email addresses, phone numbers, and so on, a hacker can call or email someone at a company requesting information while posing as another employee. The finger

has also had several exploitable security holes crackers have used to break into systems. For example, in 1988 the Morris worm exploited an overflow vulnerability in fingerd (among others) to spread. For these reasons, by the late 1990s the vast majority of sites on the Internet no longer offered the service.

Application support

It is implemented on

Unix Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...

(like

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 ...

and

macOS macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac (computer), Mac computers. Within the market of ...

Unix-like A Unix-like (sometimes referred to as UN*X or *nix) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-li ...

systems (like

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which i ...

), and current versions of

Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for ...

(finger.exe command). Other software has finger support: * ELinks *

Lynx A lynx is a type of wild cat. Lynx may also refer to: Astronomy * Lynx (constellation) * Lynx (Chinese astronomy) * Lynx X-ray Observatory, a NASA-funded mission concept for a next-generation X-ray space observatory Places Canada * Lynx, Ontar ...

Minuet A minuet (; also spelled menuet) is a social dance of French origin for two people, usually in time. The English word was adapted from the Italian ''minuetto'' and the French ''menuet''. The term also describes the musical form that accompa ...

KristallLagrange

References

External links