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CFINGERD

CFINGERD

Section: Configurable Finger Daemon (8) Updated: 18 Dec 1998
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NAME

cfingerd - Configurable finger daemon.
 

SYNOPSIS

cfingerd [ -c | -e | -o | -v ]
           -c : Check configuration
           -e : Emulate local finger w/o inetd
           -o : Turn off all finger queries
           -v : Request version information

-c checks your installed configuration. This makes sure there are no existing errors in the current cfingerd.conf file.

-e allows you to emulate a local finger on a user that exists on your system. This lets you test cfingerd on your system before installing it. Using the "-e" directive is the same as installing the software, typing "finger username@" and getting the output. Using "-e username" does the same.

-o turns off all finger queries. This makes it so that no one can finger your system - no matter what they try to do. Unlike the other options, this option is used in inetd.conf, not on the command line.

-v requests cfingerd version information.
 

DESCRIPTION

CFINGERD is a totally new, and totally configurable finger daemon - one of the first. It listenes on the finger port (port 79) to provide useful information about each user that is on your system according to the finger protocol as described in RFC 1288. Only thing is, cfingerd provides a unique twist.

CFINGERD was designed for the sole purpose of making output on finger queries configurable. If you want to change any text that is displayed during finger queries, you can configure the finger daemon to display just about anything you want.

CFINGERD also takes into account any security breaches, and attempts to close them. With the added bonus of creating ".nofinger" files, this is displayed instead of finger information, making it possible for users to keep themselves relatively anonymous from outside users. For a maximum of users privacy you should place an exact copy of /etc/cfingerd/nouser_banner.txt in your .nofinger file.
 

WHY WAS IT DONE?

The answer is simple. Security. Many sites turn off finger for the reason that they don't want outside users to see who's on their system, or get information about a specific user on their system. This seemed unfair to the rest of the users out there, so this program was created. Besides, those sites were waiting for this type of program. Many sites that originally had their finger turned off turned them back on because of cfingerd.

Many sites have complained that they wanted the ability to create a "fake-user", or a user that doesn't exist but calls a pre-written shell script. CFINGERD has taken this into account, and provides the best method possible for creating such scripts. (See cfingerd.conf(5) for more information on the configuration file.)
 

FEATURES CFINGERD PROVIDES, AND DESCRIPTIONS OF EACH

CFINGERD was totally rewritten. Why is this? Well, the older version of cfingerd had quite a few bugs, and it didn't quite do all of the things that cfingerd now does. This new version was totally revamped, and most of the bugs that were in the older version of cfingerd were removed in this one. Besides, the code in here was more compact.

Header and footer displays were a very big part of the original release of cfingerd, and shall continue to remain in all versions. Headers and footers are only displays at the beginning and ending of all finger displays, and are used as unique little "advertisements" or such.

Last time displayed is always a critical issue. It's covered in cfingerd. Cfingerd simply shows how many times this user is connected, what their idle time is on each TTY they're connected to, and whether or not they are accepting messages. If they're not accepting messages, a "[MESG-N]" display will be shown if this is the case. This display also shows the last time mail was read, and whether or not this user has mail. If this is still too much for your taste, each of these items can be disabled system wide.

Stand-alone and INETD support is compiled into the program, but only INETD support is given for the time being. The reason being is that I have not yet added the code for stand-alone daemon mode.

.nofinger files are used when a user wishes to remain anonymous. These files should be placed in their home directories, and can display anything they want. There's just a few restrictions. These .nofinger display files cannot be character devices, directories, fifos, soft or hard links, or anything else of that caliber. They must only be normal files.

Fakeusers were supported for the simple fact that many sites want to create users that don't exist, and make them execute a shell. If you want this done, then install a fake user. Read up in cfingerd.conf(5) for more information on these useful options.

Service listings were used to show what fakeusers you have installed on your system. These can be formatted however you wish, and are explained (once again) in cfingerd.conf(5).

Searching for usernames is a very powerful feature that cfingerd takes full advantage of. If you are looking for a specific username on the system, or don't know what their name is, simply use the search.pattern directive with cfingerd will search for all users containing pattern in their real name or username on that system.

Searching for usernames is NOT case sensitive. You may search for a specific username or real name, for part of the username or real ame, or for a pattern matching the entire username or the entire real ame. If you search for part of a user's name, chances are, it'll be displayed.

Warning searching will currently return the names of daemon users and users

and you will be able to search for a user on your system.

Security is a given. If you don't want to show someone something, then it won't display what you don't want. Simply edit the cfingerd.conf file and make changes. It's that simple.

Searching for usernames is NOT case sensitive. If you are searching for a specific username, or part of the user's name. If you search for part of a user's name or username, chances are, it'll be displayed.

Not just PLAN, or PROJECT but there's also an option to display your public PGP key, if you have one. This is very useful if you want to keep your mail or other information secret to yourself, and don't want "big brother" watching over your shoulder as you talk amongst yourselves. (Thanks to Andy Smith for this patch). (For your info, the standard plan file is .plan, project is .project, PGP info is .pgpkey, and XFace icon information is .xface)

Remember, any or all of these options stated above, can be turned on or off at will. If you want a specific option turned off, turn it off. :)
 

FULL LIST OF BUILTIN USER NAMES

cfingerd provides a set of builtin fake users. Two of them are also used internally by cfingerd.

@
List logged on users without .nofinger file. If the system_list_sites option is used in the main configuration file cfingerd will try to gather information from all listed hosts.
userlist@
Same as @, except that it only lists people who are idle no longer than one day. This is intended to give a better overview of who's really online at the moment of fingering.
userlist-only@
List logged on users without .nofinger file - without headers and footers. This fake user is used internally to gather system information from remote hosts for @.
userlist-online@
List logged on users without .nofinger file - without headers and footers. Only users will be listed who are idle no longer than a day. This fake user is used internally to gather system information from remote hosts for userlist@.
version@
Display version information for cfingerd.
services@
List all fake users.
search.pattern@
Search for users using the GCOS field in /etc/passwd. Only users will be displayed who don't have a .nofinger-file.
help@
Help text listing all of these.

These can be disabled in cfingerd.conf(5) as follows

@ and userlist@
Set SYSTEM_LIST to FALSE.
userlist-only@ and userlist-online@
Disable ALLOW_USERLIST_ONLY (i.e. prefix it with a minus sign) or disable SYSTEM_LIST.
version@
Disable ALLOW_CONFESSION (i.e. prefix it with a minus sign).
services@
Disable ALLOW_FAKEUSER_FINGER (i.e. prefix it with a minus sign).
search.pattern@
Disable ALLOW_SEARCHABLE_FINGER (i.e. prefix it with a minus sign).
help@
Disable ALLOW_CONFESSION (i.e. prefix it with a minus sign).

 

ERROR MESSAGES

Any error messages that result are fairly easy to debug if you know what to look for.

Segmentation Violations don't always occur, but if they ever do, you can pretty easily figure out what's going on. Unfortunately, cfingerd doesn't have any compatibility with older cfingerd.conf files, so if you get a Segmentation Violation, this (usually) means that your cfingerd.conf file needs to be replaced.

Timeouts usually mean that a script has timed out, or a connection to another site timed out.
 

SYSLOGGING MESSAGES

Well, there's no real way to describe SYSLOG messages since they can be changed as the system administrator chooses. Although, examples can be given based on the standard configuration that was distributed.

If any IP addresses cannot be matched to a name it will display a "IP: Hostname not matched".

If the renice fails (to make the program run at the highest priority) then it will display "Fatal - Nice died: (reason)".

If there is no buffer information waiting in the STDIN buffer, it will display "STDIN contains no data".

If a trusted host fingers your site, a "<- Trusted" will appear.

If a rejected host fingers your site, a "<- Rejected" will appear.

If root is fingered on your site, it will display "Root".

If a service listing was fingered on your site, it will display "Service listing".

If a user listing was requested, it will display "User listing".

If a fake user was requested, it will display "Fake user".

If "whois" data was requested, it will display "Whois request". (Note, whois was not implemented in this release, since it wasn't 'RFC' compliant.)

Any extra information pertaining to the incoming finger is displayed in the syslogging area. (It's also recommended that you reconfigure syslog.conf(5) to display to an unused VT. :)
 

PLANS

Any other options or improvements will probably come from user suggestions. :)

Later plans will make it so that you can define your own display formats for the finger display. This means that you can re-define how you want your finger display to look.
 

CONTACTING

If you like the software, and you want to learn more about the software, or want to see a feature added to it that isn't already here, then please write to cfingerd@infodrom.north.de. The project's webpage is at http://www.infodrom.north.de/cfingerd/ .

 

SEE ALSO

cfingerd.conf(5), cfingerd.text(5), finger(1), userlist(1), syslog.conf(5).


 

Index

NAME
SYNOPSIS
DESCRIPTION
WHY WAS IT DONE?
FEATURES CFINGERD PROVIDES, AND DESCRIPTIONS OF EACH
FULL LIST OF BUILTIN USER NAMES
ERROR MESSAGES
SYSLOGGING MESSAGES
PLANS
CONTACTING
SEE ALSO

This document was created by man2html, using the manual pages.
Time: 22:01:24 GMT, April 16, 2011