Introducing Zimbra authentication module for SimpleSAMLphp

While a generic LDAP authentication module for SimpleSAMLphp exists, it is hard to set-up, it requires the use and storing of an admin bind credential and is in continous development making it impossible to install a working version of this module on a released version of SimpleSAMLphp.

The Zimbra authentication module for SimpleSAMLphp makes it easy to use the Zimbra LDAP as the authentication source for your SimpleSAMLphp based SAML IDP.

  1. The Zimbra authentication module requires users to use their full email address to log-in.
  2. Login by the use of an alias email address is not and will not be supported.
  3. This module requires TLS for the connection between this module and the Zimbra LDAP.
  4. This module was designed for SimpleSAMLPhp version 2.0.4.


If you want to use 2FA this should be achieved with an additional SimpleSAMLPhp module. This module is not aware of Zimbra 2FA and it will ignore any Zimbra 2FA settings.

Installing and configuration

Set-up in config/authsources.php as follows, replace with your Zimbra server hostname:

'zimbra' => array (
    'zimbraServer' => '',
    'zimbraPort' => 389

Enable the module in config/config.php, add zimbraauth to module.enable as following example:

     'module.enable' => [
           'admin' => true,
           'zimbraauth' => true,

First use the cd command to go into the installation folder of SimpleSAMLPhp, then install this module using:

mkdir -p modules/zimbraauth/src/Auth/Source/
wget -O modules/zimbraauth/src/Auth/Source/ZimbraAuth.php
chown www-data:www-data modules/ -R  #Ubuntu
chown apache:apache modules/ -R  #RedHat

Assuming you installed SimpleSAMLPhp in simplesaml Apache location, you can test the authentication source via:

First login using your SimpleSAMLPhp admin credentials and then use a Zimbra account for testing. Use the full Zimbra email address to log-in. ( or and NOT admin or testuser)

Upon successful auth the following attributes will be available: ou, sn, givenname, mail, uid.

If this works you can set-up SimpleSAMLPhp as an IDP and use Zimbra as the authentication source see:

Bare minimum example of metadata/saml20-idp-hosted.php, notice `auth’⇒`zimbra’ is what tells SimpleSAMLPhp to use the Zimbra authentication module:

$metadata[''] = [
   'host' => '__DEFAULT__',
   'privatekey' => 'server.pem',
   'certificate' => 'server.crt',
   'auth' => 'zimbra',

Disable authentication fallback

By default Zimbra will also try to log-in using credentials from Zimbra LDAP, if you have SAML working, you should disable this fallback.

zmprov md zimbraAuthFallbackToLocal FALSE   #replace with your domain!


No comments yet.

Leave a Reply

Copyright © 2022 Zimbra, Inc. All rights reserved.

All information contained in this blog is intended for informational purposes only. Synacor, Inc. is not responsible or liable in any manner for the use or misuse of any technical content provided herein. No specific or implied warranty is provided in association with the information or application of the information provided herein, including, but not limited to, use, misuse or distribution of such information by any user. The user assumes any and all risk pertaining to the use or distribution in any form of any subject matter contained in this blog.

Legal Information | Privacy Policy | Do Not Sell My Personal Information | CCPA Disclosures