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identd(8)							     identd(8)



NAME
       identd - TCP/IP IDENT protocol server

SYNOPSIS
       identd [options]

DESCRIPTION
       Identd  is a server which implements the TCP/IP proposed standard IDENT
       user identification protocol as specified in the RFC 1413 document.

       identd operates by looking up specific TCP/IP connections and returning
       the  user name of the process owning the connection.  It can optionally
       return other information instead of a user name.

OPTIONS
       -h	 Display the available command line options.

       -V	 Displays the version and OS version it was compiled for,  and
		 then exit.

       -d	 Enables extra debugging messages.

       -C  Directs identd to parse additional configuration options from
		 the file specified.

       -i	 May be used when  starting  the  daemon  by  inetd  with  the
		 "nowait" option (see below).

       -w	 May be used when starting the daemon by inetd with the "wait"
		 option (see below).

       -I	 May be used when the daemon is started by init (see below).

       -b	 flag may be used to make the daemon run  in  standalone  mode
		 (see below).

       -u  Used  to  specify  a  user number or name to which the server
		 should switch to after binding itself to the TCP/IP port  and
		 opening the kernel devices.

       -g Used  to  specify  a  group  number  or name which the server
		 should switch to after binding itself to the TCP/IP port  and
		 opening the kernel devices.

       -p  Used  to  specify an alternative TCP port to bind to, if run
		 ning as a standalone daemon or started by init Can be	speci
		 fied  by name or by number. Defaults to the IDENT port (113).

       -t Used to specify the request timeout limit. This is the  maxi
		 mum number of seconds a server will allow a client connection
		 to be active before terminating it. It defaults to  120  sec
		 onds.

       -P
		 Specify the location of a file to store the process number of
		 the Identd daemon.

       -K
		 Control the number of threads to use for kernel lookups

       -L
		 Set the syslog facility to use instead of daemon.

       -o	 Directs identd to return OTHER instead of UNIX as the	"oper
		 ating system".

       -E	 Enables  DES  encryption  of the returned data (see below for
		 more information).

       -n	 Directs identd to always return user numbers instead of  user
		 names	(for  example  if  you	wish  to keep the user names a
		 secret).

       -N	 Directs identd to check for a file ".noident"	in  each  home
		 directory  for  the  user which the daemon is about to return
		 the user name for. If that file exists then the  daemon  will
		 give  the  error  HIDDEN-USER	instead  of  the normal USERID
		 response.

       -e	 Enables certain non-standard protocol	extensions.  Currently
		 defined extensions include the requests VERSION to return the
		 Ident daemon version and QUIT to terminate a session  (useful
		 in conjunction with the -m option).

       -m	 Enables  identd  to  use  a mode of operation that will allow
		 multiple requests to be processed per session.  Each  request
		 is  specified one per line and the responses will be returned
		 one per line. The connection will not	be  closed  until  the
		 connecting part closes its end of the line.

INSTALLATION
       The preferred way to start identd depends on how it was built.

       If  it  was  built  with  support  for multithreading then it should be
       started either from init , as a standalone daemon or from  inetd  using
       the "wait" mode (if your inetd supports it!)

       If  it  was  built without support for multithreading then it should be
       started from inetd using the normal "nowait" mode for "stream tcp" ser
       vices.  (The  main  reason being that it will be single-threaded, so it
       will only serve one client connection at a time).

       identd normally will autodetect how it was invoked so there normally is
       no need to use the four command line switches (-i, -w, -I, -b).

ENCRYPTION
       DES  encryption	is only available if the daemon was built with support
       for it enabled.

       An encryption key (1024 bytes long) should be stored in the key file  (
       /etc/identd.key	) and it should be generated using a cryptographically
       safe random generator in order to be really safe. It should not contain
       any  NUL  (0x00)  characters since this is used as a string to generate
       the real binary DES key.

       This file may contain multiple 1024 byte long keys, and the server will
       use the last key stored in that file.

       The  returned  token will contain the local and remote IP addresses and
       TCP port numbers, the local users uid number, a	timestamp,  a  random
       number,	and a checksum - all encrypted using DES. The encrypted binary
       information is then encoded in a BASE64 string (32 characters long) and
       enclosed  in  square brackets to produce a token that is transmitted to
       the remote client.

       The encrypted token can later be decrypted  by  the  idecrypt  command.
       This  program  will attempt to decrypt a token with all the keys stored
       in the key file until it succeeds (or have tried all the keys).

CONFIGURATION FILE
       The configuration file contains a list of option=value pairs.

       syslog:facility = FACILITY
		 Set which facility to use when sending syslog messages.   See
		 syslog.conf(5) for more information.

       server:user = USER
		 Set  what user (and group, from the passwd database) the dae
		 mon should run as after it has opened all the kernel handles.
		 (Default: nobody)

       server:group = GROUP
		 Override the group id (as set by the server:user option).

       server:port = PORT
		 Set  what  TCP/IP port the daemon should listen to. (Default:
		 113)

       server:backlog = LIMIT
		 Set the size of the server listen() backlog limit.

       server:pid-file = PATH
		 Set the path to the file where the  server  will  store  its
		 process id.

       server:max-request = LIMIT
		 Max  number  of  concurrent  requests	allowed.  Default is 0
		 (zero) which means "no limit".

       protocol:extensions = ON/OFF
		 Enable/disable the nonstandard protocol extensions (  VERSION
		 and QUIT currently). Default: off

       protocol:multiquery = ON/OFF
		 Enable/disable  the  multiple queries per connection feature.
		 Default: off

       protocol:timeout = SECONDS
		 Max number of seconds since connection or  last  request.  If
		 set  to  0 (zero), no timeout will be used. Default: 120 sec
		 onds.

       kernel:threads = LIMIT
		 Max number of	threads  doing	kernel	lookups  concurrently.
		 Default: 8

       kernel:buffers = LIMIT
		 Max number of queued kernel lookup requests. Default: 32

       kernel:attempts = LIMIT
		 Max number of times to retry a kernel lookup in case of fail
		 ure.  Default: 5

       result:uid-only = YES/NO
		 Disable uid->username	lookups  (only	return	uid  numbers).
		 Default: no

       result:noident = ON/OFF
		 Enable/disable  checking  for	the   ".noident" file in users
		 home directories.

       result:charset = CHARSET
		 Define the character set returned in replies.	Default:  "US-
		 ASCII"

       result:opsys = OPSYS
		 Define  the  operating  system  returned in replies. Default:
		 "UNIX"

       result:syslog-level = LEVEL
		 If set to anything other than "none", all  requested  replies
		 will  be  sent  to  the  syslog  service  with  the specified
		 severity level.  See  syslog.conf(5)  for  more  information.
		 Default: none

       result:encrypt = YES/NO
		 Enable  encryption  of  replies. Only available if Identd was
		 built with a DES encryption library.

       encrypt:key-file = PATH
		 Path to the file containing the encryption keys.

       include = PATH
		 Include (and parse) the  contents  of	another  configuration
		 file.

NOTES
       The  username  (or UID) returned ought to be the login name. However it
       (probably, for most architecture implementations) is the "real user ID"
       as stored with the process. Thus the UID returned may be different from
       the login name for setuid programs (or those running as root) which has
       done a setuid(3) call and their children. For example, it may (should?)
       be wrong for an incoming ftpd ; and we are probably interested  in  the
       running	shell, not the telnetd for an incoming telnet session. (But of
       course identd returns  info  for  outgoing  connections,  not  incoming
       ones.)

FILES
       /etc/identd.conf
	      Contains the default configuration options for identd.

       /etc/identd.key
	      If compiled with DES encryption enabled, the 1024 first bytes of
	      this file is used to  specify  the  secret  key  for  encrypting
	      replies.

       /var/run/identd/identd.pid
	      Contains (if enabled) the process number of the identd daemon.

AVAILABILITY
       The  daemon  is free software. You can redistribute it and/or modify it
       as you wish - as long as you dont claim that you wrote it.

       The source code for the latest version of  the  daemon  can  always  be
       FTPd from one of the following addresses:

       Main site:  ftp://ftp.lysator.liu.se/pub/ident/servers/

       Mirror:	   ftp://ftp.uu.net/networking/ident/servers/

       The author can be contacted at:

       Email:	   Peter Eriksson 

SEE ALSO
       idecrypt(8) , ikeygen(8) , inetd.conf(5) ,



				  8 Jan 1999			     identd(8)




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