RUNIDN(1)							     RUNIDN(1)



NAME
       runidn - A script to allow applications to use internationalized domain
       names.

SYNOPSIS
       runidn [-e local-codeset] program-name [args..]

DESCRIPTION
       runidn enables applications to use internationalized domain names with
       out  recompilation.   Just  add runidn before the application-name,
       and the application can handle non-ASCII domain	names.	 For  example,
       you can do:

	   % runidn telnet non-ASCII-hostname

       Before  using  runidn, you should set up properties related to interna
       tionalized DNS by configuring  idnkits  configuration  file  idn.conf.
       See idn.conf(5) which describes the configuration.

OPTION
       The following option is available:

       -e local-codeset
	   Specify  the  applications  local  codeset.	 If the option is not
	   specified, runidn guesses the codeset from the current locale.  See
	   the NOTE section for more details about local codeset.

IMPLEMENTATION
       runidn  is  a  small  shell script that sets up an environment variable
       called LD_PRELOAD, so  that  an	application  dynamically  links  a
       shared library libidnkitres before any other shared libraries.

       The  library  libidnkitres  provides  a special version of resolver
       functions  which  implement  features  for  handling  internationalized
       domain names.  runidn replaces the following functions with the special
       version:

	   gethostbyname
	   gethostbyname2
	   gethostbyaddr
	   gethostbyname_r
	   gethostbyname2_r
	   gethostbyaddr_r
	   getipnodebyname
	   getipnodebyaddr
	   freehostent
	   getaddrinfo
	   freeaddrinfo
	   getnameinfo

       By overriding them in the standard libraries with the  special  version
       provided by libidnkitres, runidn enables applications to use inter
       nationalized domain names.

	    These API functions accept non-ASCII domain names encoded in  the
	     local  codeset  that  the	application is using.  Also the result
	     from these APIs may contain non-ASCII domain names.

	    The normalization and codeset  conversion  between	applications
	     local  codeset and the codeset used in DNS protocol data are han
	     dled automatically, so users/applications need  not  worry  about
	     them.

       Properties  of  internationalized DNS (such as the normalization or the
       codeset used on DNS protocol data) can be configured with the  idnkits
       configuration file (idn.conf).  See idn.conf(5) for details.

NOTE
       Unless  -e option is specified, runidn tries to guess the applications
       local codeset from the applications current  locale.   However,	some
       times  it cannot guess the codeset correctly, for example if the appli
       cation does not set the locale appropriately by calling	setlocale().
       In  that  case, you can explicitly specify the local codeset by setting
       an environment variable IDN_LOCAL_CODESET.  See the section LOCAL
       CODESET in idn.conf(5) for details.

       The idea of using LD_PRELOAD to replace some functions in the stan
       dard library was taken from runsocks script distributed as part	of
       SOCKS5 reference implementation.

BUGS
       There are many cases where runidn does not work.

       Your system must support LD_PRELOAD mechanism in the first place.

       Due  to	security  reasons,  LD_PRELOAD	mechanism  is disabled for
       setuid programs in any sane systems.   So  runidn  does	not  work  for
       setuid programs such as ping or rsh.

       If your application uses a function other than the ones runidn supports
       for name resolution, you lose.

SEE ALSO
       idn.conf(5), runsocks(1)



				 April 6, 2001			     RUNIDN(1)