throw exception on LDAP error 1, which we usually do not see and is pretty generic. AD uses is for uses not enlisted in the RFC, like on issues with anonymous binds. we also try to guess this case and show a hint.

apps/user_ldap/ajax/testConfiguration.php

@@ -39,6 +39,23 @@ try {
 	if ($connection->setConfiguration($_POST)) {
 		//Configuration is okay
 		if ($connection->bind()) {
+			/*
+			 * This shiny if block is an ugly hack to find out whether anonymous
+			 * bind is possible on AD or not. Because AD happily and constantly
+			 * replies with success to any anonymous bind request, we need to
+			 * fire up a broken operation. If AD does not allow anonymous bind,
+			 * it will end up with LDAP error code 1 which is turned into an
+			 * exception by the LDAP wrapper. We catch this. Other cases may
+			 * pass (like e.g. expected syntax error).
+			 */
+			try {
+				$ldapWrapper->read($connection->getConnectionResource(), 'neverwhere', 'objectClass=*', array('dn'));
+			} catch (\Exception $e) {
+				if($e->getCode() === 1) {
+					OCP\JSON::error(array('message' => $l->t('The configuration is invalid: anonymous bind is not allowed.')));
+					exit;
+				}
+			}
 			OCP\JSON::success(array('message'
 			=> $l->t('The configuration is valid and the connection could be established!')));
 		} else {

apps/user_ldap/js/wizard/wizardTabGeneric.js

@@ -74,7 +74,13 @@ OCA = OCA || {};
 				&& !this.configModel.configuration.ldap_dn)
 			{
 				message = t('user_ldap', 'Anonymous bind is not allowed. Please provide a User DN and Password.');
+			} else if (message === 'LDAP Operations error'
+				&& !this.configModel.configuration.ldap_dn
+				&& !this.configModel.configuration.ldap_agent_password)
+			{
+				message = t('user_ldap', 'LDAP Operations error. Anonymous bind might not be allowed.');
 			}
+
 			return message;
 		},
 

apps/user_ldap/lib/ldap.php

@@ -289,6 +289,8 @@ class LDAP implements ILDAPWrapper {
 					throw new ServerNotAvailableException('Lost connection to LDAP server.');
 				} else if ($errorCode === 48) {
 					throw new \Exception('LDAP authentication method rejected');
+				} else if ($errorCode === 1) {
+					throw new \Exception('LDAP Operations error', $errorCode);
 				} else {
 					\OCP\Util::writeLog('user_ldap',
 										'LDAP error '.$errorMsg.' (' .