libexec/fingerd/fingerd.8

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.\"     @(#)fingerd.8	8.1 (Berkeley) 6/4/93
.\" $FreeBSD$
.\"
.Dd April 1, 2010
.Dt FINGERD 8
.Os
.Sh NAME
.Nm fingerd
.Nd remote user information server
.Sh SYNOPSIS
.Nm
.Op Fl d
.Op Fl k
.Op Fl s
.Op Fl l
.Op Fl p Ar filename
.Sh DESCRIPTION
The
.Nm
utility uses a simple protocol based on
.%T RFC1196
that provides an interface to
.Xr finger 1
at several network sites.
It 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
.Dq "command line" ,
thus,
.Nm
can also be used to implement other protocols in conjunction with the
.Fl p
flag.
.Pp
The
.Nm
utility is started by
.Xr inetd 8 ,
which listens for
.Tn TCP
requests at port 79.
Once connected it reads a single command line
terminated by a
.Aq Tn CRLF
which is passed to
.Xr finger 1 .
The
.Nm
utility closes its connections as soon as the output is finished.
.Pp
If the line is null (i.e., just a
.Aq Tn CRLF
is sent) then
.Xr finger 1
returns a
.Dq default
report that lists all people logged into
the system at that moment.
.Pp
If a user name is specified (e.g.\&
.Pf eric Aq Tn CRLF )
then the
response lists more extended information for only that particular user,
whether logged in or not.
Allowable
.Dq names
in the command line include both
.Dq login names
and
.Dq user names .
If a name is ambiguous, all possible derivations are returned.
.Pp
The following options may be passed to
.Nm
as server program arguments in
.Pa /etc/inetd.conf :
.Bl -tag -width indent
.It Fl d
Enable debugging mode.
In debugging mode,
.Nm
will not attempt any network-related operations on
.Va stdin ,
and it will print the full
.Nm finger
command line
to
.Va stderr
before executing it.
.It Fl k
Suppress login information.
See the description of the
.Fl k
option in
.Xr finger 1
for details.
.It Fl s
Enable secure mode.
Queries without a user name are rejected and
forwarding of queries to other remote hosts is denied.
.It Fl l
Enable logging.
The name of the host originating the query is reported via
.Xr syslog 3
at LOG_NOTICE priority.
.It Fl p
Use an alternate program as the local information provider.
The default local program
executed by
.Nm
is
.Xr finger 1 .
By specifying a customized local server,
this option allows a system manager
to have more control over what information is
provided to remote sites.
If
.Fl p
is specified,
.Nm
will also set the environment variable
.Ev FINGERD_REMOTE_HOST
to the name of the host making the request.
.El
.Sh SEE ALSO
.Xr finger 1 ,
.Xr inetd 8
.Sh HISTORY
The
.Nm
utility appeared in
.Bx 4.3 .
.Sh BUGS
Connecting directly to the server from a
.Tn TIP
or an equally narrow-minded
.Tn TELNET Ns \-protocol
user program can result
in meaningless attempts at option negotiation being sent to the
server, which will foul up the command line interpretation.
The
.Nm
utility should be taught to filter out
.Tn IAC Ns \'s
and perhaps even respond
negatively
.Pq Tn IAC WON'T
to all option commands received.