diff --git a/plugins/ldap_authentication/config.inc.php.dist b/plugins/ldap_authentication/config.inc.php.dist
new file mode 100644
index 00000000..ca745201
--- /dev/null
+++ b/plugins/ldap_authentication/config.inc.php.dist
@@ -0,0 +1,18 @@
+<?php
+
+// The id of the LDAP address book (which refers to the $rcmail_config['ldap_public'])
+// or complete addressbook definition array.
+$rcmail_config['ldap_authentication_addressbook'] = '';
+
+// This will overwrite defined filter
+$rcmail_config['ldap_authentication_filter'] = '(&(objectClass=kolabInetOrgPerson)(|(uid=%u)(mail=%fu)(alias=%fu)))';
+
+// Use this fields (from fieldmap configuration) to get authentication ID
+$rcmail_config['ldap_authentication_login'] = 'email';
+
+// Use this fields (from fieldmap configuration) for default identity
+$rcmail_config['ldap_authentication_name']  = 'name';
+$rcmail_config['ldap_authentication_alias'] = 'alias';
+$rcmail_config['ldap_authentication_email']  = 'email';
+
+?>
diff --git a/plugins/ldap_authentication/ldap_authentication.php b/plugins/ldap_authentication/ldap_authentication.php
new file mode 100644
index 00000000..d491a8c3
--- /dev/null
+++ b/plugins/ldap_authentication/ldap_authentication.php
@@ -0,0 +1,140 @@
+<?php
+
+/**
+ * LDAP Authentication
+ *
+ * Authenticate on LDAP server, finds canonized authentication ID for IMAP
+ * and for new users create identity based on LDAP information.
+ *
+ * @version 0.1
+ * @author Aleksander Machniak <machniak@kolabsys.com>
+ *
+ * Copyright (C) 2011, Kolab Systems AG
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+class ldap_authentication extends rcube_plugin
+{
+    public $task = 'login';
+
+    private $ldap;
+    private $data = array();
+
+	function init()
+	{
+		$this->add_hook('authenticate', array($this, 'authenticate'));
+		$this->add_hook('user_create', array($this, 'user_create'));
+	}
+
+	function user_create($args)
+	{
+		if (!empty($this->data['user_email']))
+    		$args['user_email'] = $this->data['user_email'];
+		if (!empty($this->data['user_name']))
+	    	$args['user_name'] = $this->data['user_name'];
+		if (!empty($this->data['user_alias']))
+	    	$args['user_alias'] = $this->data['user_alias'];
+
+		return $args;
+	}
+
+    function authenticate($args)
+    {
+        if ($this->init_ldap()) {
+            $rcmail = rcmail::get_instance();
+            $filter = $rcmail->config->get('ldap_authentication_filter');
+            $domain = $rcmail->config->get('username_domain');
+
+            // get username and host
+            $user = $args['user'];
+            $host = rcube_parse_host($args['host']);
+
+            if (!empty($domain) && strpos($user, '@') === false) {
+                if (is_array($domain) && isset($domain[$args['host']]))
+                    $user .= '@'.rcube_parse_host($domain[$host], $host);
+                else if (is_string($domain))
+                    $user .= '@'.rcube_parse_host($domain, $host);
+            }
+
+            // replace variables in filter
+            list($u, $d) = explode('@', $user);
+            $dc = 'dc='.strtr($d, array('.' => ',dc=')); // hierarchal domain string
+            $replaces = array('%dc' => $dc, '%d' => $d, '%fu' => $user, '%u' => $u);
+
+            $filter = strtr($filter, $replaces);
+
+            // get record
+            $this->ldap->set_filter($filter);
+            $results = $this->ldap->list_records();
+
+            if (count($results->records) == 1) {
+                $record = $results->records[0];
+
+                $login_attr = $rcmail->config->get('ldap_authentication_login');
+                $alias_attr = $rcmail->config->get('ldap_authentication_alias');
+                $name_attr  = $rcmail->config->get('ldap_authentication_name');
+
+                if ($login_attr)
+                    $this->data['user_login'] = is_array($record[$login_attr]) ? $record[$login_attr][0] : $record[$login_attr];
+                if ($alias_attr)
+                    $this->data['user_alias'] = is_array($record[$alias_attr]) ? $record[$alias_attr][0] : $record[$alias_attr];
+                if ($name_attr)
+                    $this->data['user_name'] = is_array($record[$name_attr]) ? $record[$name_attr][0] : $record[$name_attr];
+
+                if ($this->data['user_login'])
+                    $args['user'] = $this->data['user_login'];
+            }
+        }
+
+        return $args;
+    }
+
+    private function init_ldap()
+    {
+        if ($this->ldap)
+            return $this->ldap->ready;
+
+        $this->load_config();
+        $rcmail = rcmail::get_instance();
+
+        $addressbook = $rcmail->config->get('ldap_authentication_addressbook');
+
+        if (!is_array($addressbook)) {
+            $ldap_config = (array)$rcmail->config->get('ldap_public');
+            $addressbook = $ldap_config[$addressbook];
+        }
+
+        if (empty($addressbook)) {
+            return false;
+        }
+
+        $this->ldap = new ldap_authentication_ldap_backend(
+            $addressbook,
+            $rcmail->config->get('ldap_debug'),
+            $rcmail->config->mail_domain($_SESSION['imap_host'])
+        );
+
+        return $this->ldap->ready;
+    }
+}
+
+class ldap_authentication_ldap_backend extends rcube_ldap
+{
+    function set_filter($filter)
+    {
+        if ($filter)
+            $this->prop['filter'] = $filter;
+    }
+}