Graham Ollis

NAME

AnyEvent::Ident - Simple asynchronous ident client and server

VERSION

version 0.06

SYNOPSIS

client:

 use AnyEvent::Ident qw( ident_client );
 
 ident_client '127.0.0.1', 113, $server_port, $client_port, sub {
   my($res) = @_; # isa AnyEvent::Client::Response 
   if($res->is_success)
   {
     print "user: ", $res->username, "\n"
     print "os:   ", $res->os, "\n"
   }
   else
   {
     warn "Ident error: " $res->error_type;
   }
 };

server:

 use AnyEvent::Ident qw( ident_server );
 
 ident_server '127.0.0.1', 113, sub {
   my $tx = shift;
   if($tx->req->server_port == 400
   && $tx->req->client_port == 500)
   {
     $tx->reply_with_user('UNIX', 'grimlock');
   }
   else
   {
     $tx->reply_with_error('NO-USER');
   }
 };

DESCRIPTION

This module provides a simple procedural interface to AnyEvent::Ident::Client and AnyEvent::Ident::Server.

FUNCTIONS

ident_server $hostname, $port, $callback

Start an ident server listening to the address given by $hostname on port $port. For each request $callback will be called and passed in an instance of AnyEvent::Ident::Transaction.

ident_client $hostname, $port, $server_port, $client_port, $callback

Make an ident request with the ident server at $hostname on port $port with the given port pair $server_port,$client_port. When the response comes back call $callback, with an instance of AnyEvent::Ident::Response.

WHY

Why use this distribution instead of Net::Ident?

  • Works under Windows (MSWin32)

    Net::Ident installs (even passing its tests) on Windows, but it does not work. It may not work in some UNIX environments depending on your headers and libraries.

  • Works with AnyEvent

    This distribution will work with any event loop supported by AnyEvent.

  • Server Included

    This distribution comes with a server, which is handy for testing (take a peek at the test suite for Mojolicious::Plugin::Ident to see what I mean.

Sometimes Net::Ident might be more appropriate. Net::Ident has only core dependencies and will work on older Perls. This module requires AnyEvent. Net::Ident may be easier to wrap your head around if you don't need or want to run under an event loop.

CAVEATS

ident is an oldish protocol and almost nobody uses it anymore. The RFC for the protocol clearly states that ident should not be used for authentication, at most it should be used only for audit (for example annotation of log files). In Windows and possibly other operating systems, an unprivileged user can listen to port 113 and on any untrusted network, a remote ident server is not a secure authentication mechanism.

No modern operating systems enable the ident service by default, so you can't expect it to be there unless you have control of the server and have specifically enabled it.

Most of the time a client wanting to use the ident protocol expects to find ident listening to port 113, which on many platforms (such as UNIX) requires special privileges (such as root).

Under Linux you can use iptables to forward requests from port 113 to an unprivileged port. I was able to use this incantation to forward port 113 to port 8113:

 # iptables -t nat -A PREROUTING -p tcp --dport 113 -j REDIRECT --to-port 8113
 # iptables -t nat -I OUTPUT -p tcp -d 127.0.0.1 --dport 113 -j REDIRECT --to-port 8113

The first rule is sufficient for external clients, the second rule was required for clients connecting via the loopback interface (localhost).

SEE ALSO

RFC1413, AnyEvent::Ident::Client, AnyEvent::Ident::Server

AUTHOR

Graham Ollis <plicease@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2013 by Graham Ollis.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.