Finger Protocol

Information about Finger Protocol

In computer networking, the Name/Finger protocol and the Finger user information protocol are simple network protocols for the exchange of human-oriented status and user information.

Name/Finger protocol

The Name/Finger protocol, written by David Zimmerman, is based on Request for comments document 742 (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 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 technology that worked for remote users over a network.

Prior to the finger program, the only way to get this information was with a who program that showed IDs and terminal line numbers for logged-in users, and people used to run their fingers down the who list. Earnest named his program after this concept.

Finger user information protocol

Finger is based on the Transmission Control Protocol, using TCP port 79 decimal. The local host opens a TCP connection to a remote host on the Finger port. An RUIP (Remote User Information Program) becomes available on the remote end of the connection to process the request. The local host sends the RUIP a 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 closing its end of the connection.

The Finger user information protocol is based on RFC 1288 (The Finger User Information Protocol, December 1991). Typically the server side of the protocol is implemented by a program fingerd (for finger daemon), while the client 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. It is most often implemented on Unix or Unix-like systems.

The program would supply information such as whether a user is currently logged-on, e-mail address, 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. Often this file (maintained by the user) contains either useful information about the user's current activities, 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 the Internet, but later was considered questionable for privacy and security reasons. Finger information has been frequently used by crackers as a way to initiate a social engineering 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 cracker can telephone or email someone at a company requesting information while posing as another employee. The finger daemon has also had several exploitable security holes which crackers have used to break into systems. The Morris worm exploited an overflow vulnerability in fingerd (among others) to spread.

For these reasons, while finger was widely used during the early days of Internet, by the 1990s the vast majority of sites on the internet no longer offered the service. Notable exceptions include John Carmack and Justin Frankel, who until recently still updated their status information occasionally. In late 2005, John Carmack switched to using a blog, instead of his old .plan site.

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• • [ e] Unix command line programs and builtins (more)
File and file system management	cat chattr cd chmod chown chgrp cksum cmp cp du df file fsck fuser ln ls lsof mkdir mount mv pwd rm rmdir split touch
Process management	at chroot crontab exit kill killall nice pgrep pidof pkill ps sleep time top wait watch
User Management/Environment	env finger id logname mesg passwd su sudo uname uptime w wall who whoami write
Text processing	awk comm cut ed ex fmt head iconv join less more paste sed sort tac tail tr uniq wc xargs
Shell programming	basename echo expr false printf test true unset
Printing: lp Communications: inetd netstat ping rlogin nc traceroute Searching: find grep strings Miscellaneous: banner bc cal dd man size yes

Computer networking is the engineering discipline concerned with communication between computer systems or devices. Networking, routers, routing protocols, and networking over the public Internet have their specifications defined in documents called RFCs.
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protocol is a convention or standard that controls or enables the connection, communication, and data transfer between two computing endpoints. In its simplest form, a protocol can be defined as the rules governing the syntax, semantics, and synchronization of communication.
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Request for Comments (RFC) documents are a series of memoranda encompassing new research, innovations, and methodologies applicable to Internet technologies.
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Lester Donald Earnest was born in the United States on December 17, 1930. He began his career as a computer programmer in 1954 during a stint as a U.S. Navy Aviation Electronics Officer & Digital Computer Project Officer at Naval Air Development Center, Johnsville, Pennsylvania http://www.
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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.
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The standard Unix command who displays a list of users who are currently logged into a computer.

The who command is related to the command w, which provides the same information but also displays additional data and statistics.
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A finger is a type of digit, an organ of manipulation and sensation found in the hands of humans and other primates. Normally humans have five digits on each hand (exceptions are polydactyly, hypodactyly and digit loss).
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Server Computer

The inside/front of a server computer

Connects to:

Internet via one of

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daemon (IPA pronunciation: /'dimən/ or /'deɪmən/^[1]
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Status is a state, condition or situation.

social status
economic status
legal status
Status quo
Status symbol
A category of the grammar of Semitic languages, see nunation, status constructus

Status
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command line interface or CLI is a method of interacting with an operating system or software using a command line interpreter. This command line interpreter may be a text terminal, terminal emulator, or remote shell client such as PuTTY.
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Unix (officially trademarked as UNIX®) is a computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs including Ken Thompson, Dennis Ritchie and Douglas McIlroy.
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e-mail address identifies a location to which e-mail messages can be delivered. The term "e-mail address" is also used as the formal pre-registered authoritative electronic mailing delivery site for an individual (example: an attorney's e-mail address registered for delivery of
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In computing, a home directory is a directory which contains the personal files of a particular user of the system.

Separating user data from system-wide data avoids redundancy and makes backups of important files relatively simple.
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Humour or humor (see spelling differences) is the ability or quality of people, objects, or situations to evoke feelings of amusement in other people. The term encompasses a form of entertainment or human communication which evokes such feelings, or which makes people laugh
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A black hat is a person who compromises the security of a computer system without permission from an authorized party, typically with malicious intent. The term white hat is used for a person who is ethically opposed to the abuse of computer systems, but is frequently no less
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Social engineering is a collection of techniques used to manipulate people into performing actions or divulging confidential information.^[1] While similar to a confidence trick or simple fraud, the term typically applies to trickery for information gathering or computer
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daemon (IPA pronunciation: /'dimən/ or /'deɪmən/^[1]
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The Morris worm or Internet worm was one of the first computer worms distributed via the Internet; it is considered the first worm and was certainly the first to gain significant mainstream media attention.
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Internet is a worldwide, publicly accessible series of interconnected computer networks that transmit data by packet switching using the standard Internet Protocol (IP). It is a "network of networks" that consists of millions of smaller domestic, academic, business, and government
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Centuries: 19th century - 20th century - 21st century

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For the band, see .

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Justin Frankel is an American computer programmer best known for his work on the Winamp media player application and for inventing the Gnutella peer-to-peer system. He's also the founder of Cockos Incorporated which creates music production and development software such as the
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blog (a portmanteau of web log) is a website where entries are written in chronological order and commonly displayed in reverse chronological order. "Blog" can also be used as a verb, meaning to maintain or add content to a blog.
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Printing: lp Communications: inetd netstat ping rlogin nc traceroute Searching: find grep strings Miscellaneous: banner bc cal dd man size yes
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The cat command is a standard Unix program used to concatenate and display files. The name is from , a synonym of concatenate.

Specification

The Single Unix Specification specifies the behavior that each of the files given in sequence as arguments will write their
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chattr is a UNIX program that allows a user to set certain attributes to a file. Mostly chattr is used to make files immutable so that password files and certain system files cannot be erased during software upgrades.
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cd, sometimes also available as chdir (change directory), is a command line command to change the current working directory in operating systems such as Unix, Windows and DOS.
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The chmod command (abbreviated from change mode) is a shell command in Unix and Unix-like environments.

When executed, the command can change file system modes of files and directories. The modes include permissions and special modes.
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