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Duo Protection for Google Workspace (Google G Suite) with Duo Access Gateway

Last Updated: December 8th, 2020

Duo offers a variety of methods for adding two-factor authentication and flexible security policies to G Suite SSO logins, complete with inline self-service enrollment and Duo Prompt.

Looking for a cloud-hosted SSO solution? Try Duo Single Sign-On for Google Workspace (Google G Suite).

These same instructions provide SAML SSO to Google Cloud Platform (GCP) as well, as G Suite and GCP share the underlying domain's authentication configuration. Learn more about SSO and GCP.


As business applications move from on-premises to cloud hosted solutions, users experience password fatigue due to disparate logons for different applications. Single sign-on (SSO) technologies seek to unify identities across systems and reduce the number of different credentials a user has to remember or input to gain access to resources.

While SSO is convenient for users, it presents new security challenges. If a user's primary password is compromised, attackers may be able to gain access to multiple resources. In addition, as sensitive information makes its way to cloud-hosted services it is even more important to secure access by implementing two-factor authentication.

Duo Access Gateway

Duo Access Gateway (DAG), our on-premises SSO product, layers Duo's strong authentication and flexible policy engine on top of G Suite logins using the Security Assertion Markup Language (SAML) 2.0 authentication standard. Duo Access Gateway acts as an identity provider (IdP), authenticating your users using existing on-premises or cloud-based directory credentials and prompting for two-factor authentication before permitting access to G Suite.

Duo Access Gateway is included in the Duo Beyond, Duo Access, and Duo MFA plans, which also include the ability to define policies that enforce unique controls for each individual SSO application. For example, you can require that Salesforce users complete two-factor authentication at every login, but only once every seven days when accessing G Suite. Duo checks the user, device, and network against an application's policy before allowing access to the application.

Note: If you are using Google as your authentication source for Duo Access Gateway you cannot protect application logins to that same G Suite account with Duo Access Gateway.

Deploy or Update Duo Access Gateway

  1. Install Duo Access Gateway on a server in your DMZ. Follow our instructions for deploying the server and configuring DAG settings. Note that it is not possible to use Google OpenID Connect or G Suite as a SAML IdP as the DAG authentication source for G Suite application logins.
  2. Add the attributes from the table below that correspond to the Duo attributes Mail attribute and Username attribute in the "Attributes" field when configuring your Active Directory or OpenLDAP authentication source in the DAG admin console, separated by a comma. For example, if Active Directory is your authentication source, enter mail,sAMAccountName in the "Attributes" field.

    Duo Attribute Active Directory OpenLDAP
    Mail attribute mail mail
    Username attribute sAMAccountName uid

    If your organization uses other directory attributes than the ones listed here then enter those attribute names instead. If you've already configured the attributes list for another cloud service provider, append the additional attributes not already present to the list, separated by a comma.

  3. After completing the initial DAG configuration steps, click Applications on the left side of the Duo Access Gateway admin console.

  4. Scroll down the Applications page to the Metadata section. This is the information you need to provide to G Suite when configuring SSO. Click the Download Certificate link to obtain the token signing certificate (the downloaded file is named "dag.crt").

    DAG Metadata Information

Enable G Suite SSO

Add the Duo Access Gateway as a new single sign-on provider for G Suite.

  1. Log on to the Google Admin console and navigate to Security > Set up single sign-on.

  2. Check the Setup SSO with third party identity provider box.

  3. Copy the SSO URL information from the Duo Access Gateway admin console Metadata display and paste it into the G Suite Sign-in page URL field.


  4. Copy the Logout URL information from the Duo Access Gateway admin console Metadata display and paste it into the G Suite Sign-out page URL field.


  5. If your organization has a web service for Active Directory password changes enter that URL into the "Change password URL" field. Otherwise, copy the Logout URL into the "Change password URL" field as well.

  6. The "Verification certificate" is the DAG Metadata certificate supplied by Duo Access Gateway. Click the link to select the dag.crt file you downloaded from the DAG admin console "Application" page earlier.

  7. Check the Use a domain-specific issuer box if your users access G Suite using your own domain name (such as

  8. After you've entered all the required information click SAVE CHANGES.

    G Suite Single Sign-On Setting Edit

Learn more about G Suite SSO at the G Suite Help site.

Create the G Suite Application in Duo

  1. Log on to the Duo Admin Panel and navigate to Applications.

  2. Click Protect an Application and locate the entry for G Suite with a protection type of "2FA with SSO self-hosted (Duo Access Gateway)" in the applications list. Click Protect to the far-right to start configuring G Suite. See Protecting Applications for more information about protecting applications in Duo and additional application options.

  3. Enter your G Suite domain name in the Domain name field.

  4. G Suite uses the Mail attribute when authenticating. We've mapped Mail attribute to DAG supported authentication source attributes as follows:

    Duo Attribute Active Directory OpenLDAP SAML IdP Google Azure
    Mail attribute mail mail mail email mail

    If you are using a non-standard email attribute for your authentication source, check the Custom attributes box and enter the name of the attribute you wish to use instead.

  5. Click Save Configuration to generate a downloadable configuration file.

    Duo G Suite Application Settings

  6. You can adjust additional settings for your new SAML application at this time — like changing the application's name from the default value, enabling self-service, or assigning a group policy — or come back and change the application's policies and settings after you finish SSO setup. If you do update any settings, click the Save Changes button when done.

  7. Click the Download your configuration file link to obtain the G Suite application settings (as a JSON file).

    Important: This file contains information that uniquely identifies this application to Duo. Secure this file as you would any other sensitive or password information. Don't share it with unauthorized individuals or email it to anyone under any circumstances!

Add the G Suite Application to Duo Access Gateway

Before you do this, verify that you updated the "Attributes" list for your Duo Access Gateway authentication source as specified here.

  1. Return to the Applications page of the DAG admin console session.

  2. Click the Choose File button in the "Add Application" section of the page and locate the G Suite SAML application JSON file you downloaded from the Duo Admin Panel earlier. Click the Upload button after selecting the JSON configuration file.

  3. The G Suite SAML application is added.

    G Suite Application Added

G Suite Session Duration

G Suite Business, Education, and Enterprise editions have the ability to customize how long a session remains valid after logging in with a third-party SAML IdP (like Duo Access Gateway). Set this in the Google Admin console under SecuritySession Control. Be sure not to change the session duration to a length that is less than the Duo Access Gateway's Session Duration (found under Settings in the Access Gateway admin console) if you want to always force users to login and complete Duo MFA again when the G Suite session expires. Learn more about this G Suite option at the Google support site.

Verify SSO

You can log on to G Suite using your organization's domain login page e.g. for Gmail. This redirects to the Duo Access Gateway login page. Enter your primary directory logon information, approve Duo two-factor authentication, and get redirected back to the G Suite site after authenticating.

DAG Login and Authentication Prompt

Users can also enter the email address that is mapped to name ID on the main G Suite login page or any and click the Sign In button (with a blank password) to be forwarded to the DAG logon site.

Congratulations! Your G Suite users now authenticate using Duo Access Gateway.

Enable Hostname Whitelisting

If you plan to permit use of WebAuthn authentication methods (security keys, U2F tokens, or Touch ID), Duo recommends enabling hostname whitelisting for this application and any others that show the inline Duo Prompt before onboarding your end-users.

Microsoft AD FS

Microsoft's Active Directory Federation Services (AD FS) is a popular choice for SSO because it easily integrates with the AD identity store many organizations already have deployed. Duo's support for cloud applications and SSO drops in to an existing AD FS installation to provide secondary authentication after a user passes primary authentication (successful Active Directory logon).

If you don't already have AD federation running the first step is to install and configure Microsoft AD FS in your organization. Deployment Guides for AD FS versions 2.1, and 3.0/4.0 are available from Microsoft.

Once your AD FS services are up and running, the second step is to configure the SSO partnership between your AD FS service and the external cloud resource, in this case G Suite. Learn more about configuring G Suite SSO with AD FS at the G Suite Help site.

After you have successfully configured and tested AD FS SSO login to G Suite using your AD domain credentials, you can then install the Duo AD FS integration. AD FS protection is included with Duo's paid plans.

With the Duo integration for AD FS installed, users pass primary authentication to the AD FS service as usual. Once primary authentication succeeds, users are forwarded to the Duo service for secondary authentication. After approving logon using one of Duo's authentication methods, the user is fully logged in to G Suite.

Other Identity Partners

Using a third-party SSO provider for cloud application access? Duo partners with leading cloud SSO providers like Okta and OneLogin to secure access with our strong and flexible authentication platform.

You can also use Duo two-factor authentication with CAS and Shibboleth on-premises IdPs.


Need some help? Try searching our Knowledge Base articles or Community discussions. For further assistance, contact Support.