Azure Active Directory Seamless Single Sign-On: Quickstart

Deploy Seamless Single Sign-On

Azure Active Directory (Azure AD) Seamless Single Sign-On (Seamless SSO) automatically signs in users when they are on their corporate desktops that are connected to your corporate network. Seamless SSO provides your users with easy access to your cloud-based applications without needing any additional on-premises components.

To deploy Seamless SSO, follow these steps.

Step 1: Check the prerequisites

Ensure that the following prerequisites are in place:

• Set up your Azure AD Connect server: If you use Pass-through Authentication as your sign-in method, no additional prerequisite check is required. If you use password hash synchronization as your sign-in method, and if there is a firewall between Azure AD Connect and Azure AD, ensure that:

  • You use version 1.1.644.0 or later of Azure AD Connect.

  • If your firewall or proxy allows, add the connections to the allowed list for *.msappproxy.net URLs over port 443. If you require a specific URL rather than a wildcard for proxy configuration, you can configure tenantid.registration.msappproxy.net, where tenantid is the GUID of the tenant where you are configuring the feature. If URL-based proxy exceptions are not possible in your organization, you can instead allow access to the Azure datacenter IP ranges, which are updated weekly. This prerequisite is applicable only when you enable the feature. It is not required for actual user sign-ins.

    Note

    Azure AD Connect versions 1.1.557.0, 1.1.558.0, 1.1.561.0, and 1.1.614.0 have a problem related to password hash synchronization. If you don't intend to use password hash synchronization in conjunction with Pass-through Authentication, read the Azure AD Connect release notes to learn more.

    Note

    If you have an outgoing HTTP proxy, make sure this URL, autologon.microsoftazuread-sso.com, is on the allowed list. You should specify this URL explicitly since wildcard may not be accepted.

• Use a supported Azure AD Connect topology: Ensure that you are using one of Azure AD Connect's supported topologies described here.

  Note

  Seamless SSO supports multiple AD forests, whether there are AD trusts between them or not.

• Set up domain administrator credentials: You need to have domain administrator credentials for each Active Directory forest that:

  • You synchronize to Azure AD through Azure AD Connect.
  • Contains users you want to enable for Seamless SSO.

• Enable modern authentication: You need to enable modern authentication on your tenant for this feature to work.

• Use the latest versions of Microsoft 365 clients: To get a silent sign-on experience with Microsoft 365 clients (Outlook, Word, Excel, and others), your users need to use versions 16.0.8730.xxxx or above.

Step 2: Enable the feature

Enable Seamless SSO through Azure AD Connect.

Note

You can also enable Seamless SSO using PowerShell if Azure AD Connect doesn't meet your requirements. Use this option if you have more than one domain per Active Directory forest, and you want to be more targeted about the domain you want to enable Seamless SSO for.

If you're doing a fresh installation of Azure AD Connect, choose the custom installation path. At the User sign-in page, select the Enable single sign on option.

Note

The option will be available for selection only if the Sign On method is Password Hash Synchronization or Pass-through Authentication.

If you already have an installation of Azure AD Connect, select the Change user sign-in page in Azure AD Connect, and then select Next. If you are using Azure AD Connect versions 1.1.880.0 or above, the Enable single sign on option will be selected by default. If you are using older versions of Azure AD Connect, select the Enable single sign on option.

Continue through the wizard until you get to the Enable single sign on page. Provide domain administrator credentials for each Active Directory forest that:

• You synchronize to Azure AD through Azure AD Connect.
• Contains users you want to enable for Seamless SSO.

After completion of the wizard, Seamless SSO is enabled on your tenant.

Note

The domain administrator credentials are not stored in Azure AD Connect or in Azure AD. They're used only to enable the feature.

Follow these instructions to verify that you have enabled Seamless SSO correctly:

1. Sign in to the Azure Active Directory administrative center with the Hybrid Identity Administrator or hybrid identity administrator credentials for your tenant.
2. Select Azure Active Directory in the left pane.
3. Select Azure AD Connect.
4. Verify that the Seamless single sign-on feature appears as Enabled.

Important

Seamless SSO creates a computer account named AZUREADSSOACC in your on-premises Active Directory (AD) in each AD forest. The AZUREADSSOACC computer account needs to be strongly protected for security reasons. Only Domain Admins should be able to manage the computer account. Ensure that Kerberos delegation on the computer account is disabled, and that no other account in Active Directory has delegation permissions on the AZUREADSSOACC computer account. Store the computer account in an Organization Unit (OU) where they are safe from accidental deletions and where only Domain Admins have access.

Note

If you are using Pass-the-Hash and Credential Theft Mitigation architectures in your on-premises environment, make appropriate changes to ensure that the AZUREADSSOACC computer account doesn't end up in the Quarantine container.

Step 3: Roll out the feature

You can gradually roll out Seamless SSO to your users using the instructions provided below. You start by adding the following Azure AD URL to all or selected users' Intranet zone settings by using Group Policy in Active Directory:

• https://autologon.microsoftazuread-sso.com

In addition, you need to enable an Intranet zone policy setting called Allow updates to status bar via script through Group Policy.

Note

The following instructions work only for Internet Explorer, Microsoft Edge, and Google Chrome on Windows (if it shares a set of trusted site URLs with Internet Explorer). Read the next section for instructions on how to set up Mozilla Firefox and Google Chrome on macOS.

Why do you need to modify users' Intranet zone settings?

By default, the browser automatically calculates the correct zone, either Internet or Intranet, from a specific URL. For example, http://contoso/ maps to the Intranet zone, whereas http://intranet.contoso.com/ maps to the Internet zone (because the URL contains a period). Browsers will not send Kerberos tickets to a cloud endpoint, like the Azure AD URL, unless you explicitly add the URL to the browser's Intranet zone.

There are two ways to modify users' Intranet zone settings:

Option	Admin consideration	User experience
Group policy	Admin locks down editing of Intranet zone settings	Users cannot modify their own settings
Group policy preference	Admin allows editing on Intranet zone settings	Users can modify their own settings

"Group policy" option - Detailed steps

1. Open the Group Policy Management Editor tool.

2. Edit the group policy that's applied to some or all your users. This example uses Default Domain Policy.

3. Browse to User Configuration > Policies > Administrative Templates > Windows Components > Internet Explorer > Internet Control Panel > Security Page. Then select Site to Zone Assignment List.

4. Enable the policy, and then enter the following values in the dialog box:

   • Value name: The Azure AD URL where the Kerberos tickets are forwarded.

   • Value (Data): 1 indicates the Intranet zone.

     The result looks like this:

     Value name: https://autologon.microsoftazuread-sso.com

     Value (Data): 1

   Note

   If you want to disallow some users from using Seamless SSO (for instance, if these users sign in on shared kiosks), set the preceding values to 4. This action adds the Azure AD URL to the Restricted zone, and fails Seamless SSO all the time.

5. Select OK, and then select OK again.

   

6. Browse to User Configuration > Policies > Administrative Templates > Windows Components > Internet Explorer > Internet Control Panel > Security Page > Intranet Zone. Then select Allow updates to status bar via script.

   

7. Enable the policy setting, and then select OK.

   

"Group policy preference" option - Detailed steps

1. Open the Group Policy Management Editor tool.

2. Edit the group policy that's applied to some or all your users. This example uses Default Domain Policy.

3. Browse to User Configuration > Preferences > Windows Settings > Registry > New > Registry item.

   

4. Enter the following values in appropriate fields and click OK.

   • Key Path: Software\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap\Domains\microsoftazuread-sso.com\autologon

   • Value name: https

   • Value type: REG_DWORD

   • Value data: 00000001

     

     

Browser considerations

Mozilla Firefox (all platforms)

If you are using the Authentication policy settings in your environment, ensure that you add Azure AD's URL (https://autologon.microsoftazuread-sso.com) to the SPNEGO section. You can also set the PrivateBrowsing option to true to allow seamless SSO in private browsing mode.

Safari (macOS)

Ensure that the machine running the macOS is joined to AD. Instructions for AD-joining your macOS device is outside the scope of this article.

Microsoft Edge based on Chromium (all platforms)

If you have overridden the AuthNegotiateDelegateAllowlist or the AuthServerAllowlist policy settings in your environment, ensure that you add Azure AD's URL (https://autologon.microsoftazuread-sso.com) to them as well.

Microsoft Edge based on Chromium (macOS and other non-Windows platforms)

For Microsoft Edge based on Chromium on macOS and other non-Windows platforms, refer to the Microsoft Edge based on Chromium Policy List for information on how to add the Azure AD URL for integrated authentication to your allow-list.

Google Chrome (all platforms)

If you have overridden the AuthNegotiateDelegateAllowlist or the AuthServerAllowlist policy settings in your environment, ensure that you add Azure AD's URL (https://autologon.microsoftazuread-sso.com) to them as well.

macOS

The use of third-party Active Directory Group Policy extensions to roll out the Azure AD URL to Firefox and Google Chrome to macOS users is outside the scope of this article.

Known browser limitations

Seamless SSO doesn't work on Internet Explorer if the browser is running in Enhanced Protected mode. Seamless SSO supports the next version of Microsoft Edge based on Chromium and it works in InPrivate and Guest mode by design. Microsoft Edge (legacy) is no longer supported.

AmbientAuthenticationInPrivateModesEnabledmay need to be configured for InPrivate and / or guest users based on the corresponding documentations:

• Microsoft Edge Chromium
• Google Chrome

Step 4: Test the feature

To test the feature for a specific user, ensure that all the following conditions are in place:

• The user signs in on a corporate device.
• The device is joined to your Active Directory domain. The device doesn't need to be Azure AD Joined.
• The device has a direct connection to your domain controller (DC), either on the corporate wired or wireless network or via a remote access connection, such as a VPN connection.
• You have rolled out the feature to this user through Group Policy.

To test the scenario where the user enters only the username, but not the password:

• Sign in to https://myapps.microsoft.com/. Be sure to either clear the browser cache or use a new private browser session with any of the supported browsers in private mode.

To test the scenario where the user doesn't have to enter the username or the password, use one of these steps:

• Sign in to https://myapps.microsoft.com/contoso.onmicrosoft.com Be sure to either clear the browser cache or use a new private browser session with any of the supported browsers in private mode. Replace contoso with your tenant's name.
• Sign in to https://myapps.microsoft.com/contoso.com in a new private browser session. Replace contoso.com with a verified domain (not a federated domain) on your tenant.

Step 5: Roll over keys

In Step 2, Azure AD Connect creates computer accounts (representing Azure AD) in all the Active Directory forests on which you have enabled Seamless SSO. To learn more, see Azure Active Directory Seamless Single Sign-On: Technical deep dive.

Important

The Kerberos decryption key on a computer account, if leaked, can be used to generate Kerberos tickets for any user in its AD forest. Malicious actors can then impersonate Azure AD sign-ins for compromised users. We highly recommend that you periodically roll over these Kerberos decryption keys - at least once every 30 days.

For instructions on how to roll over keys, see Azure Active Directory Seamless Single Sign-On: Frequently asked questions.

Important

You don't need to do this step immediately after you have enabled the feature. Roll over the Kerberos decryption keys at least once every 30 days.

Next steps

• Technical deep dive: Understand how the Seamless Single Sign-On feature works.
• Frequently asked questions: Get answers to frequently asked questions about Seamless Single Sign-On.
• Troubleshoot: Learn how to resolve common problems with the Seamless Single Sign-On feature.
• UserVoice: Use the Azure Active Directory Forum to file new feature requests.