Linux man page for fingerd.8

fingerd(8) -- Linux man page

NAME

fingerd - remote user information server

SYNOPSIS

fingerd [-wulf ] [-pL path ] [-t timeout ]

DESCRIPTION

Fingerd is a simple daemon based on RFC1196 that provides an interface to the ``finger'' program at most 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.

If the -w option is given, remote users will get an additional ``Welcome to ...'' banner which also shows some informations (e.g. uptime, operating system name and release) about the system the fingerd is running on. Some sites may consider this a security risk as it gives out information that may be useful to crackers.

If the -u option is given, requests of the form ``finger @host'' are rejected.

If the -l option is given, information about requests made is logged. This option probably violates users' privacy and should not be used on multiuser boxes.

If the -f option is given, finger forwarding (user@host1@host2) is allowed. Useful behind firewalls, but probably not wise for security and resource reasons.

The -p option allows specification of an alternate location for fingerd to find the ``finger'' program. The -L option is equivalent.

The -t option specifies the time to wait for a request before closing the connection. A value of 0 waits forever. The default is 60 seconds.

Options to fingerd should be specified in /etc/xinetd.d/finger

The finger protocol consists mostly of specifying command arguments. The xinetd(8) ``super-server'' runs fingerd for TCP requests received on port 79. Once connected fingerd reads a single command line terminated by a Aq Tn CRLF which is passed to finger(1). It closes its connections as soon as all output is finished.

If the line is empty (i.e. just a Aq Tn CRLF is sent) then finger returns a ``default'' report that lists all people logged into the system at that moment. This feature is blocked by the -u option.

If a user name is specified (e.g. eric Aq 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.

RESTRICTIONS

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.