Finger (internet protocol)

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Finger in the TCP / IP protocol stack :
application finger
transport TCP
Internet IP ( IPv4 , IPv6 )
Network access Ethernet Token
bus 		Token
ring 		FDDI ...

Finger displays information about a specific user on a local system or on a remote computer, or is used to determine the availability of a specific host in IP networks.

The information displayed includes:

  • Username (login name)
  • Full name of the user
  • Registration time
  • Time span, how long the user has been active or inactive
  • Terminal from which the user logged on

But finger can also be used to convey other information. For this purpose, a user can create a file named '.plan' or '.project' in his home directory, the content of which is delivered when finger-accessed. This was used for years, for example, to keep users up to date on the current Linux kernel version.

In order to query information about a user on a remote host, the host must support the finger service , which is rarely the case today. As a rule, this then occupies TCP port 79. The following command is executed on the command line : 

 finger benutzername@hostname

history

The finger protocol is one of the older protocols from the Internet protocol family . It is based on the original NAME / FINGER protocol ( RFC 742 ), which implements the connection to the name and finger programs and was defined as RFC in 1977 . The Finger program was originally developed by Les Earnest in 1971 . Earnest developed the program to give users the opportunity to learn information from other users on the network. Before, the only way to get this information was through the who program , which displayed the IDs and terminal numbers of the logged in users. The current version of RFC 1288 of the protocol definition was established in 1991.

Today, like other protocols with similar functionality, finger is viewed as a glaring security leak, as it enables outsiders to obtain detailed information about the identity of users and their habits. For computer security related to fingers, see also social engineering .

Thimbl

Thimbl is a definition for JSON -structured data, which can be stored as finger information for a user. In this way, a kind of microblogging platform is set up on Finger , which could be comparable to Twitter or Diaspora , but relies on well-known protocols and standards and thus offers greater reliability and independence from individual providers.

There are already several projects for Thimbl that try to create end-user-friendly clients.

See also

Web links