fingerd.8

操作系统设计与实现源码

.\" Copyright (c) 1980 Regents of the University of California.
.\" All rights reserved.  The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\"
.\"	@(#)fingerd.8c	6.1 (Berkeley) 5/23/86
.\"
.TH FINGERD 8 "May 23, 1986"
.UC 6
.SH NAME
fingerd, in.fingerd \- remote user information server
.SH SYNOPSIS
.B "finger stream tcp nowait nobody /usr/sbin/in.fingerd in.fingerd"
.br
.B "tcpd finger /usr/sbin/in.fingerd in.fingerd"
.SH DESCRIPTION
.B Fingerd
is a simple protocol based on RFC742 that provides an interface to the
Name and Finger programs at several network sites.
The program is 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''.
.PP
.B Fingerd
listens for TCP requests at port 79.
Once connected it reads a single command line
terminated by a <CRLF> which is passed to
.BR finger (1).
.B Fingerd
closes its connections as soon as the output is finished.
.PP
If the line is null (i.e. just a <CRLF> is sent) then 
.B finger
returns a ``default'' report that lists all people logged into
the system at that moment.
.PP
If a user name is specified (e.g. eric<CRLF>) then the
response lists more extended information for only that particular user,
whether logged in or not.
Allowable ``names'' in the command line include both ``login names''
and ``user names''.
If a name is ambiguous, all possible derivations are returned.
.SH SEE ALSO
.BR finger (1).
.SH BUGS
Connecting directly to the server from a TIP
or an equally narrow-minded TELNET-protocol user program can result
in meaningless attempts at option negotiation being sent to the
server, which will foul up the command line interpretation.
.B Fingerd
should be taught to filter out IAC's and perhaps even respond
negatively (IAC WON'T) to all option commands received.