External user authentication

⚠⚠ Warning: As of Version 3.0 this app uses namespace \OCA\UserExternal now. You MUST change your config to adopt to this change. See examples below. ⚠⚠

Authenticate user login against IMAP, SMB, FTP, WebDAV, HTTP BasicAuth, SSH and XMPP

Passwords are not stored locally; authentication always happens against the remote server.

It stores users and their display name in its own database table users_external. When modifying the user_backends configuration, you need to update the database table's backend field, or your users will lose their configured display name.

If something does not work, check the log file at nextcloud/data/nextcloud.log.

⚠⚠ Warning: If you are using more than one backend or especially one backend more often than once, make sure that you still have resp. get unique uids in the database. ⚠⚠

⚠⚠ Warning: If you are using tools like fail2ban (https://www.fail2ban.org) to protect your authentication source (e.g. IMAP server), be sure to disable it for the host that runs user_external. Otherwise a single user failing to login too many times can practically DoS your whole Nextcloud installation because fail2ban will then block the Nextcloud IP address. ⚠⚠ Instead, make sure the bruteforce protection app for Nextcloud is installed and configured correctly.

FTP

Authenticate Nextcloud users against a FTP server.

Configuration

You only need to supply the FTP host name or IP.

The second - optional - parameter determines if SSL should be used or not.

Add the following to config.php:

'user_backends' => array(
    array(
        'class' => '\OCA\UserExternal\FTP',
        'arguments' => array('127.0.0.1'),
    ),
),

To enable SSL connections via ftps, append a second parameter true:

'user_backends' => array(
    array(
        'class' => '\OCA\UserExternal\FTP',
        'arguments' => array('127.0.0.1', true),
    ),
),

Dependencies

PHP automatically contains basic FTP support.

For SSL-secured FTP connections via ftps, the PHP openssl extension needs to be activated.

IMAP

Authenticate Nextcloud users against an IMAP server. IMAP user and password need to be given for the Nextcloud login.

Configuration

The parameters are host, port, sslmode, domain. Possible values for sslmode are ssl or tls. Add the following to your config.php:

'user_backends' => array(
    array(
        'class' => '\OCA\UserExternal\IMAP',
        'arguments' => array(
            '127.0.0.1', 993, 'ssl', 'example.com', true, false
        ),
    ),
),

This connects to the IMAP server on IP 127.0.0.1. The default port is 143. However, note that parameter order matters and if you want to restrict the domain (4th parameter), you need to also specify the port (2nd parameter) and sslmode (3rd parameter; set to null for insecure connection). If a domain name (e.g. example.com) is specified, then this makes sure that only users from this domain will be allowed to login. If the fifth parameter is set to true, after successfull login the domain part will be striped and the rest used as username in Nextcloud. e.g. 'username@example.com' will be 'username' in Nextcloud. The sixth parameter toggles whether on creation of the user, it is added to a group corresponding to the name of the domain part of the address.

⚠⚠ Warning: If you are upgrading from versions <0.6.0, beside adapting your config.php you also have to change the backend column in the users_external table of the database. In your pre 0.6.0 database it may look like {127.0.0.1:993/imap/ssl/readonly}INBOX or similar, but now it has to be just 127.0.0.1 for everything to work flawless again. ⚠⚠

Samba

Utilizes the smbclient executable to authenticate against a windows network machine via SMB.

Configuration

The only supported parameter is the hostname of the remote machine.

Add the following to your config.php:

'user_backends' => array(
    array(
        'class' => '\OCA\UserExternal\SMB',
        'arguments' => array('127.0.0.1'),
    ),
),

Dependencies

The smbclient executable needs to be installed and accessible within $PATH.

WebDAV

Authenticate users by a WebDAV call. You can use any WebDAV server, Nextcloud server or other web server to authenticate. It should return http 200 for right credentials and http 401 for wrong ones.

Attention: This app is not compatible with the LDAP user and group backend. This app is not the WebDAV interface of Nextcloud, if you don't understand what it does then do not enable it.

Configuration

The only supported parameter is the URL of the web server.

Add the following to your config.php:

'user_backends' => array(
    array(
        'class' => '\OCA\UserExternal\WebDavAuth',
        'arguments' => array('https://example.com/webdav'),
    ),
),

BasicAuth

Authenticate users by an HTTP Basic access authentication call. HTTP server of your choice to authenticate. It should return HTTP 2xx for correct credentials and an appropriate other error code for wrong ones or refused access. The HTTP server must respond to any requests to the target URL with the "www-authenticate" header set. Otherwise BasicAuth considers itself to be misconfigured or the HTTP server unfit for authentication.

Configuration

The only supported parameter is the URL of the web server where the authentication happens.

⚠⚠ Warning: make sure to use the URL of a correctly configured HTTP Basic authenticating server. If the server always responds with a HTTP 2xx response without validating the users, this would allow anyone to log in to your Nextcloud instance with any username / password combination. ⚠⚠

Add the following to your config.php:

'user_backends' => array(
    array(
        'class' => '\OCA\UserExternal\BasicAuth',
        'arguments' => array('https://example.com/basic_auth'),
    ),
),

SSH

Authenticates users via SSH. You can use any SSH2 server, but it must accept password authentication.

Configuration

The supported parameters are the hostname and the port (default 22) of the remote machine.

Add the following to your config.php:

'user_backends' => array(
    array(
        'class' => '\OCA\UserExternal\SSH',
        'arguments' => array('127.0.0.1', '22'),
    ),
),

Dependencies

Requires the php-ssh2 PECL module installed.

XMPP (Prosody)

Authenticate Nextcloud users against a Prosody XMPP MySQL database. Prosody user and password need to be given for the Nextcloud login.

Configuration

Add the following to your config.php:

'user_backends' => array (
    0 => array (
        'class' => '\OCA\UserExternal\XMPP',
            'arguments' => array (
                0 => 'dbhost',
                1 => 'prosodydb',
                2 => 'dbuser',
                3 => 'dbuserpassword',
                4 => 'xmppdomain',
                5 => true,
            ),
        ),
),

0 - Database Host 1 - Prosody Database Name 2 - Database User 3 - Database User Password 4 - XMPP Domain 5 - Hashed Passwords in Database (true) / Plaintext Passwords in Database (false)

⚠⚠ Warning: If you need to set 5 (Hashed Password in Database) to false, your Prosody Instance is storing passwords in plaintext. This is insecure and not recommended. We highly recommend that you change your Prosody configuration to protect the passwords of your Prosody users. ⚠⚠

Alternatives

Other extensions allow connecting to external user databases directly via SQL, which may be faster:

• user_sql
• user_backend_sql_raw