diff --git a/application/config/constants.php b/application/config/constants.php
index f21b6c962..cbbf55d8b 100644
--- a/application/config/constants.php
+++ b/application/config/constants.php
@@ -57,14 +57,6 @@ define('AUTH_SUCCESS',				0);
 define('AUTH_NOT_AUTHENTICATED',	1);
 define('AUTH_INVALID_CREDENTIALS',	2);
 
-/*
-|--------------------------------------------------------------------------
-| LDAP constants
-|--------------------------------------------------------------------------
-*/
-define('LDAP_NO_USER_DN',			10);
-define('LDAP_TOO_MANY_USER_DN',		11);
-
 /*
 |--------------------------------------------------------------------------
 | Language constants
diff --git a/application/config/ldap.php b/application/config/ldap.php
index b7134e3ce..be8474c1e 100644
--- a/application/config/ldap.php
+++ b/application/config/ldap.php
@@ -17,7 +17,8 @@ if (defined('LDAP_SERVER')) // 1st LDAP server
 		'basedn'	=> LDAP_BASE_DN,
 		'username'	=> LDAP_BIND_USER,
 		'password'	=> LDAP_BIND_PASSWORD,
-		'usf'		=> LDAP_USER_SEARCH_FILTER
+		'usf'		=> LDAP_USER_SEARCH_FILTER,
+		'timeout'	=> 1
 	);
 }
 
@@ -30,7 +31,8 @@ if (defined('LDAP2_SERVER')) // 2nd LDAP server
 		'basedn'	=> LDAP2_BASE_DN,
 		'username'	=> LDAP2_BIND_USER,
 		'password'	=> LDAP2_BIND_PASSWORD,
-		'usf'		=> LDAP2_USER_SEARCH_FILTER
+		'usf'		=> LDAP2_USER_SEARCH_FILTER,
+		'timeout'	=> 1
 	);
 }
 
@@ -45,7 +47,8 @@ if (defined('LDAP_SERVER')) // 1st LDAP server
 		'basedn'	=> LDAP_BASE_DN,
 		'username'	=> LDAP_BIND_USER,
 		'password'	=> LDAP_BIND_PASSWORD,
-		'usf'		=> LDAP_USER_SEARCH_FILTER
+		'usf'		=> LDAP_USER_SEARCH_FILTER,
+		'timeout'	=> 1
 	);
 }
 
@@ -58,6 +61,8 @@ if (defined('LDAP2_SERVER')) // 2nd LDAP server
 		'basedn'	=> LDAP2_BASE_DN,
 		'username'	=> LDAP2_BIND_USER,
 		'password'	=> LDAP2_BIND_PASSWORD,
-		'usf'		=> LDAP2_USER_SEARCH_FILTER
+		'usf'		=> LDAP2_USER_SEARCH_FILTER,
+		'timeout'	=> 1
 	);
 }
+
diff --git a/application/libraries/AuthLDAPLib.php b/application/libraries/AuthLDAPLib.php
new file mode 100644
index 000000000..711b7f5b9
--- /dev/null
+++ b/application/libraries/AuthLDAPLib.php
@@ -0,0 +1,309 @@
+<?php
+
+class AuthLDAPLib
+{
+	const LDAP_CONF_FILE = 'ldap'; // LDAP config file name
+
+	// LDAP codes
+	const LDAP_NO_USER_DN = 10; // No users found
+	const LDAP_TOO_MANY_USER_DN = 11; // More then one user found
+
+	// LDAP configuration array elements
+	const SERVER = 'server';
+	const PORT = 'port';
+	const STARTTLS = 'starttls';
+	const BASEDN = 'basedn';
+	const USERNAME = 'username';
+	const PASSWORD = 'password';
+	const USF = 'usf';
+	const TIMEOUT = 'timeout';
+
+	const DN = 'dn'; // LDAP dn name
+
+	const LDAP_PROTOCOL_VERSION = 3; // Specifies the LDAP protocol to be used (V2 or V3) V2 is deprecated
+	const LDAP_REFERRALS = 0; // Specifies whether to automatically follow referrals returned by the LDAP server (0 = disabled)
+	const LDAP_INVALID_CREDENTIALS = 49; // LDAP invalid credentials code
+	const LDAP_DEFAULT_TIMEOUT = 1; // Default LDAP timeout in seconds
+
+	/**
+	 * Sets the properties and loads the LDAP configuration
+	 */
+	public function __construct()
+	{
+		// Gets CI instance
+		$this->_ci =& get_instance();
+
+		// Loads the LogLib
+		$this->_ci->load->library('LogLib');
+	}
+
+	//------------------------------------------------------------------------------------------------------------------
+	// Public methods
+
+	/**
+	 * Checks if the given credentials are valid on one of the configured LDAP servers
+	 */
+	public function checkUsernamePassword($username, $password)
+	{
+		$authenticated = false;
+
+		if (isEmptyString($username) || isEmptyString($password)) return error('Wrong username and password');
+
+		$ldapConfigArrays = $this->_loadConfig(); // NOTE: always the last to be called!
+
+		// For each configured LDAP server
+		foreach ($ldapConfigArrays as $ldapConfigs)
+		{
+			// Check if the LDAP server is up and running
+			if (!$this->_servicePing($ldapConfigs))
+			{
+				// If not available log debug and skip to the next configured server
+				$this->_ci->loglib->logError('This LDAP server is not available: '.$ldapConfigs[self::SERVER]);
+				continue;
+			}
+
+			// Connection without username and passoword _or_ with the configured username and password
+			$noCredentialsConnectResult = $this->_connect($ldapConfigs);
+			if (isError($noCredentialsConnectResult)) // If an error occurred
+			{
+				// If the error is due to invalid credentials or
+				// the LDAP server does not support anonymous authentication
+				if (getCode($noCredentialsConnectResult) == AUTH_INVALID_CREDENTIALS)
+				{
+					$this->_ci->loglib->logDebug(getError($noCredentialsConnectResult).' on server '.$ldapConfigs[self::SERVER]);
+				}
+				else // otherwise if it was due to a fatal error
+				{
+					$this->_ci->loglib->logError(getError($noCredentialsConnectResult).' on server '.$ldapConfigs[self::SERVER]);
+				}
+
+				continue; // anyway skip to the next configured server
+			}
+
+			// If it is a success
+			$noCredentialsConnection = getData($noCredentialsConnectResult);
+
+			// Check if the user exists on this LDAP server
+			$userDNResult = $this->_getUserDN(
+				$noCredentialsConnection,
+				$ldapConfigs[self::BASEDN],
+				$ldapConfigs[self::USF],
+				$username
+			);
+			// If an error occurred or the user was not found or many users were found
+			if (isError($userDNResult))
+			{
+				// Log debug and skip to the next configured server
+				// If the error is due to invalid credentials or
+				// the LDAP server does not support anonymous authentication
+				if (getCode($userDNResult) == self::LDAP_NO_USER_DN)
+				{
+					$this->_ci->loglib->logDebug(getError($userDNResult).' on server '.$ldapConfigs[self::SERVER]);
+				}
+				elseif (getCode($userDNResult) == self::LDAP_TOO_MANY_USER_DN)
+				{
+					$this->_ci->loglib->logDebug(getError($userDNResult).' on server '.$ldapConfigs[self::SERVER]);
+				}
+				else // otherwise if it was due to a fatal error
+				{
+					$this->_ci->loglib->logError(getError($userDNResult).' on server '.$ldapConfigs[self::SERVER]);
+				}
+
+				$this->_close($noCredentialsConnection); // Close the current LDAP connection
+				continue; // anyway skip to the next configured server
+			}
+
+			$this->_close($noCredentialsConnection); // Close the current LDAP connection
+
+			// Connect to LDAP with the userDN and password
+			$credentialsConnectResult = $this->_connect($ldapConfigs, getData($userDNResult), $password);
+			if (isError($credentialsConnectResult)) // If an error occurred
+			{
+				// Log debug and skip to the next configured server
+				$this->_ci->loglib->logError(getError($credentialsConnectResult).' on server '.$ldapConfigs[self::SERVER]);
+				continue;
+			}
+			else // otherwise the user is authenticated
+			{
+				$this->_close(getData($credentialsConnectResult));
+				$authenticated = true;
+				break;
+			}
+		}
+
+		return $authenticated;
+	}
+
+	//------------------------------------------------------------------------------------------------------------------
+	// Private methods
+
+	/**
+	 * Loads the LDAP configuration file and returns the LDAP configuration array
+	 */
+	private function _loadConfig()
+	{
+		// Tries to require the LDAP configuration file...
+		// ...first in the ENVIRONMENT subdirectory...
+		if (file_exists(APPPATH.'config/'.ENVIRONMENT.'/'.self::LDAP_CONF_FILE.'.php'))
+		{
+			require_once(APPPATH.'config/'.ENVIRONMENT.'/'.self::LDAP_CONF_FILE.'.php');
+		}
+		else // ...then in the default config directory
+		{
+			require_once(APPPATH.'config/'.self::LDAP_CONF_FILE.'.php');
+		}
+
+		return $ldap[$ldap_active_group];
+	}
+
+	/**
+	 * Establish a connection to LDAP with the given LDAP configuration array and eventually with
+	 * with a given username and password
+	 */
+	private function _connect($ldapConfigs, $username = null, $password = null)
+	{
+		// Checks if the LDAP configuraion is empty
+		if (isEmptyArray($ldapConfigs)) return error('Wrong parameters given');
+
+		// LDAP connection
+		$ldapConnection = @ldap_connect($ldapConfigs[self::SERVER].':'.$ldapConfigs[self::PORT]);
+		if ($ldapConnection) // if success
+		{
+			// Sets the LDAP protocol version
+			if (!@ldap_set_option($ldapConnection, LDAP_OPT_PROTOCOL_VERSION, self::LDAP_PROTOCOL_VERSION))
+			{
+				return error('Was not possible to set the protocol version using LDAP sever '.$ldapConfigs[self::SERVER]);
+			}
+
+			// Enable/disable the LDAP referrals
+			if (!@ldap_set_option($ldapConnection, LDAP_OPT_REFERRALS, self::LDAP_REFERRALS))
+			{
+				return error('Was not possible to enable referrals using LDAP sever '.$ldapConfigs[self::SERVER]);
+			}
+
+			// Starts TLS if required
+			if ($ldapConfigs[self::STARTTLS] === true && !@ldap_start_tls($ldapConnection))
+			{
+				return error('Was not possible to enable TLS using LDAP sever '.$ldapConfigs[self::SERVER]);
+			}
+
+			// If username or password are not provided...
+			if (isEmptyString($username) || isEmptyString($password))
+			{
+				// ...use those provided by the configuration
+				$username = $ldapConfigs[self::USERNAME];
+				$password = $ldapConfigs[self::PASSWORD];
+			}
+
+			// Binds to LDAP directory
+			if (!@ldap_bind($ldapConnection, $username, $password))
+			{
+				// Wrong username and/or password
+				if (ldap_errno($ldapConnection) == self::LDAP_INVALID_CREDENTIALS)
+				{
+					return error('Invalid credentials', AUTH_INVALID_CREDENTIALS);
+				}
+				else // Error
+				{
+					return error('Was not possible to bind to the LDAP sever '.$ldapConfigs[self::SERVER]);
+				}
+			}
+
+			return success($ldapConnection); // connected!!!
+		}
+		else // Connection error
+		{
+			return error('An error occurred while connecting to the LDAP server '.$ldapConfigs[self::SERVER]);
+		}
+	}
+
+	/**
+	 * Check if the network service is up and running
+	 */
+	private function _servicePing($ldapConfigs)
+	{
+		// Set the default timeout
+		$timeout = self::LDAP_DEFAULT_TIMEOUT;
+
+		// If a timeout was configured for this server then use it
+		if (isset($ldapConfigs[self::TIMEOUT])) $timeout = $ldapConfigs[self::TIMEOUT];
+
+		// The LDAP server name or URL
+		$host = $ldapConfigs[self::SERVER];
+
+		// If it is a URL
+		if (strpos($ldapConfigs[self::SERVER], 'ldap://') !== false
+			|| strpos($ldapConfigs[self::SERVER], 'ldaps://') !== false)
+		{
+			// Get the host from the URL
+			$host = parse_url($ldapConfigs[self::SERVER], PHP_URL_HOST);
+		}
+
+		// Check if the given host answers on the given port using the given timeout
+		if ($op = @fsockopen($host, $ldapConfigs[self::PORT], $errno, $errstr, $timeout))
+		{
+			// If it works then close the socket connection
+			fclose($op);
+			return true;
+		}
+
+		return false; // otherwise this server is not up or LDAP service is not running on the given port
+	}
+
+	/**
+	 * Close the current connection to LDAP if present
+	 */
+	private function _close($connection)
+	{
+		@ldap_unbind($connection);
+	}
+
+	/**
+	 * Get the user DN from LDAP using the given username
+	 */
+	private function _getUserDN($connection, $baseDN, $usf, $username)
+	{
+		$userDN = error('AuthLDAPLib->_getUserDN() failed');
+
+		// Tries to search for a user DN using the given username
+		$searchResultIdentifier = @ldap_search(
+			$connection,
+			$baseDN,
+			$usf.'='.$username
+		);
+		if (!$searchResultIdentifier) // Error
+		{
+			$userDN = error(ldap_error($connection));
+		}
+
+		// Counts the number of found entries
+		$countEntries = @ldap_count_entries($connection, $searchResultIdentifier);
+		if ($countEntries === false) // Error
+		{
+			$userDN = error(ldap_error($connection));
+		}
+		elseif ($countEntries == 0)
+		{
+			$userDN = error('No user DN were found with username: '.$username, self::LDAP_NO_USER_DN);
+		}
+		elseif ($countEntries > 1)
+		{
+			$userDN = error('Too many users DN were found with username: '.$username, self::LDAP_TOO_MANY_USER_DN);
+		}
+		else // One entry was found
+		{
+			$entries = @ldap_get_entries($connection, $searchResultIdentifier);
+			if (!$entries) // Error
+			{
+				$userDN = error(ldap_error($connection));
+			}
+			else
+			{
+				$userDN = success($entries[0][self::DN]);
+			}
+		}
+
+		return $userDN;
+	}
+}
+
diff --git a/application/libraries/AuthLib.php b/application/libraries/AuthLib.php
index 67a527655..ae30d41fa 100644
--- a/application/libraries/AuthLib.php
+++ b/application/libraries/AuthLib.php
@@ -385,7 +385,7 @@ class AuthLib
 		// Invalid credentials
 		// NOTE: this is a corner case because of the HTTP basic authentication
 		if (getCode($hta) == AUTH_NOT_AUTHENTICATED || getCode($hta) == AUTH_INVALID_CREDENTIALS
-			|| getCode($hta) == LDAP_NO_USER_DN || getCode($hta) == LDAP_TOO_MANY_USER_DN)
+			|| getCode($hta) == AuthLDAPLib::LDAP_NO_USER_DN || getCode($hta) == AuthLDAPLib::LDAP_TOO_MANY_USER_DN)
 		{
 			$this->_showInvalidAuthentication(); // this also stop the execution
 		}
@@ -404,37 +404,12 @@ class AuthLib
 	{
 		$ldap = error('Not authenticated', AUTH_NOT_AUTHENTICATED); // by default is NOT authenticated
 
-		$this->_ci->load->library('LDAPLib'); // Loads the LDAP library
+		$this->_ci->load->library('AuthLDAPLib'); // Loads the LDAP library
 
-		$ldapConnection = $this->_ci->ldaplib->anonymousConnect(); // connect anonymously!
-		if (isSuccess($ldapConnection)) // connected!!
+		// If it is possible to authenticate on LDAP with the given username and password
+		if ($this->_ci->authldaplib->checkUsernamePassword($username, $password) === true)
 		{
-			// Get the user DN from LDAP
-			$userDN = $this->_ci->ldaplib->getUserDN($username);
-			if (isSuccess($userDN)) // got it!
-			{
-				$this->_ci->ldaplib->close(); // close the previous LDAP anonymous connection
-
-				// Connects to LDAP using the last working configuration + the retrieved user DN + the provided password
-				$ldapConnection = $this->_ci->ldaplib->connectUsernamePassword(getData($userDN), $password);
-				if (isSuccess($ldapConnection)) // connected!
-				{
-					$this->_ci->ldaplib->close(); // close the previous connection
-					$ldap = success('Authenticated', AUTH_SUCCESS); // authenticated!
-				}
-				else // blocking error
-				{
-					$ldap = $ldapConnection;
-				}
-			}
-			else // blocking error
-			{
-				$ldap = $userDN;
-			}
-		}
-		else // blocking error
-		{
-			$ldap = $ldapConnection;
+			$ldap = success('Authenticated', AUTH_SUCCESS); // authenticated!
 		}
 
 		return $ldap;
diff --git a/application/libraries/LDAPLib.php b/application/libraries/LDAPLib.php
deleted file mode 100644
index 195dddc88..000000000
--- a/application/libraries/LDAPLib.php
+++ /dev/null
@@ -1,228 +0,0 @@
-<?php
-
-class LDAPLib
-{
-	const LDAP_CONF_FILE = 'ldap'; // LDAP config file name
-
-	// LDAP configuration array elements
-	const SERVER = 'server';
-	const PORT = 'port';
-	const STARTTLS = 'starttls';
-	const BASEDN = 'basedn';
-	const USERNAME = 'username';
-	const PASSWORD = 'password';
-	const USF = 'usf';
-
-	const DN = 'dn'; // LDAP dn name
-
-	const LDAP_PROTOCOL_VERSION = 3; // Specifies the LDAP protocol to be used (V2 or V3) V2 is deprecated
-	const LDAP_REFERRALS = 0; // Specifies whether to automatically follow referrals returned by the LDAP server (0 = disabled)
-	const LDAP_INVALID_CREDENTIALS = 49; // LDAP invalid credentials code
-
-	// Private properties
-	private $_connection;
-	private $_workingConfigArray;
-	private $_ldapConfigArray;
-
-	/**
-	 * Sets the properties and loads the LDAP configuration
-	 */
-	public function __construct()
-	{
-		$this->_connection = null;
-		$this->_workingConfigArray = null;
-		$this->_ldapConfigArray = null;
-
-		$this->_loadConfig(); // NOTE: always the last to be called!
-	}
-
-	//------------------------------------------------------------------------------------------------------------------
-	// Public methods
-
-	/**
-	 * Tries to connect to LDAP using configurations in property _ldapConfigArray
-	 * The first that works is used and stored in property _workingConfigArray
-	 * The LDAP connection link is stored in _connection
-	 */
-	public function anonymousConnect()
-	{
-		$connect = error('Did not found a working LDAP configuration');
-
-		// Loops through LDAP configurations
-		foreach ($this->_ldapConfigArray as $ldapConfigs)
-		{
-			// Tries to establish a connection
-			$connect = $this->_connect($ldapConfigs);
-			if (isSuccess($connect))
-			{
-				break; // found a working LDAP configuration and successfully connected!
-			}
-			else
-			{
-				$this->close(); // close the eventually established connection
-			}
-		}
-
-		return $connect;
-	}
-
-	/**
-	 * Tries to connect using the given username and password and the last working configuration with anonymous connection
-	 */
-	public function connectUsernamePassword($username, $password)
-	{
-		if (isEmptyString($username) || isEmptyString($password)) return error('Wrong username and password');
-
-		return $this->_connect($this->_workingConfigArray, $username, $password);
-	}
-
-	/**
-	 * Close the current connection to LDAP if present
-	 */
-	public function close()
-	{
-		if ($this->_connection != null) @ldap_unbind($this->_connection);
-	}
-
-	/**
-	 * Get the user DN from LDAP using the given username
-	 */
-	public function getUserDN($username)
-	{
-		$userDN = error('No user DN were found', LDAP_NO_USER_DN);
-
-		// Tries to search for a user DN using the given username
-		$searchResultIdentifier = @ldap_search(
-			$this->_connection,
-			$this->_workingConfigArray[self::BASEDN],
-			$this->_workingConfigArray[self::USF].'='.$username
-		);
-		if (!$searchResultIdentifier) // Error
-		{
-			$userDN = error(ldap_error($this->_connection));
-		}
-
-		// Counts the number of found entries
-		$countEntries = @ldap_count_entries($this->_connection, $searchResultIdentifier);
-		if ($countEntries === false) // Error
-		{
-			$userDN = error(ldap_error($this->_connection));
-		}
-		elseif ($countEntries == 0)
-		{
-			$userDN = error('No user DN were found', LDAP_NO_USER_DN);
-		}
-		elseif ($countEntries > 1)
-		{
-			$userDN = error('Too many users DN were found', LDAP_TOO_MANY_USER_DN);
-		}
-		else // One entry was found
-		{
-			$entries = @ldap_get_entries($this->_connection, $searchResultIdentifier);
-			if (!$entries) // Error
-			{
-				$userDN = error(ldap_error($this->_connection));
-			}
-			else
-			{
-				$userDN = success($entries[0][self::DN]);
-			}
-		}
-
-		return $userDN;
-	}
-
-	//------------------------------------------------------------------------------------------------------------------
-	// Private methods
-
-	/**
-	 * Loads the LDAP configuration file and store the LDAP configuration array into _ldapConfigArray property
-	 */
-	private function _loadConfig()
-	{
-		// Tries to require the LDAP configuration file...
-		// ...first in the ENVIRONMENT subdirectory...
-		if (file_exists(APPPATH.'config/'.ENVIRONMENT.'/'.self::LDAP_CONF_FILE.'.php'))
-		{
-			require_once(APPPATH.'config/'.ENVIRONMENT.'/'.self::LDAP_CONF_FILE.'.php');
-		}
-		else // ...then in the default config directory
-		{
-			require_once(APPPATH.'config/'.self::LDAP_CONF_FILE.'.php');
-		}
-
-		$this->_ldapConfigArray = $ldap[$ldap_active_group]; // store the active LDAP configuration array
-	}
-
-	/**
-	 * Establish a connection to LDAP with the given LDAP configuration array and eventually with
-	 * with a given username and password
-	 */
-	private function _connect($ldapConfigs, $username = null, $password = null)
-	{
-		// Checks if the LDAP configuraion is empty
-		if (isEmptyArray($ldapConfigs))
-		{
-			return error('Wrong parameters given');
-		}
-
-		// LDAP connection
-		$ldapConnection = @ldap_connect($ldapConfigs[self::SERVER].':'.$ldapConfigs[self::PORT]);
-		if ($ldapConnection) // if success
-		{
-			// Sets the LDAP protocol version
-			if (!@ldap_set_option($ldapConnection, LDAP_OPT_PROTOCOL_VERSION, self::LDAP_PROTOCOL_VERSION))
-			{
-				return error(ldap_error($ldapConnection));
-			}
-
-			// Enable/disable the LDAP referrals
-			if (!@ldap_set_option($ldapConnection, LDAP_OPT_REFERRALS, self::LDAP_REFERRALS))
-			{
-				return error(ldap_error($ldapConnection));
-			}
-
-			// Starts TLS if required
-			if ($ldapConfigs[self::STARTTLS] === true)
-			{
-				if (!@ldap_start_tls($ldapConnection))
-				{
-					return error(ldap_error($ldapConnection));
-				}
-			}
-
-			// If username and password are not provided...
-			if ($username == null || $password == null)
-			{
-				// ...uses those provided by the configuration
-				$username = $ldapConfigs[self::USERNAME];
-				$password = $ldapConfigs[self::PASSWORD];
-			}
-
-			// Binds to LDAP directory
-			if (!@ldap_bind($ldapConnection, $username, $password))
-			{
-				// Wrong username and/or password
-				if (ldap_errno($ldapConnection) == self::LDAP_INVALID_CREDENTIALS)
-				{
-					return error('Invalid credentials', AUTH_INVALID_CREDENTIALS);
-				}
-				else // Error
-				{
-					return error(ldap_error($ldapConnection));
-				}
-			}
-
-			$this->_connection = $ldapConnection; // save the connection into _connection property
-			$this->_workingConfigArray = $ldapConfigs; // save the working LDAP configuration into _workingConfigArray property
-
-			return success('Connected'); // connected!!!
-		}
-		else // Connection error
-		{
-			return error(
-				'An error occurred while connecting to the LDAP server: '.$ldapConfigs[self::SERVER].':'.$ldapConfigs[self::PORT]
-			);
-		}
-	}
-}