Single Sign-On with Okta

This guide explains how to enable single sign-on (SSO) for applications being proxied by F5 NGINX Plus. The solution uses OpenID Connect as the authentication mechanism, with Okta as the Identity Provider (IdP), and NGINX Plus as the Relying Party, or OIDC client application that verifies user identity.

Note

This guide applies to NGINX Plus Release 36 and later. In earlier versions, NGINX Plus relied on an njs-based solution, which required NGINX JavaScript files, key-value stores, and advanced OpenID Connect logic. Starting from NGINX Plus version R34, the new OpenID Connect module simplifies this process to just a few directives.

Prerequisites

• An Okta administrator account with privileges to create and manage applications.

• An NGINX Plus subscription and NGINX Plus Release 36 or later. For installation instructions, see Installing NGINX Plus.

• A domain name pointing to your NGINX Plus instance, for example, demo.example.com.

Configure Okta

In Okta, register a new application for NGINX Plus as the OIDC client to obtain the Client ID, Client Secret, and required OIDC endpoints.

1. Log in to your Okta admin console.

2. In the Admin Console, go to Applications > Applications.

3. Select Create App Integration.

4. In Create a new app integration, select:

   • Sign-in method: OIDC - OpenID Connect.

   • Application type: Web Application.

   • Select Next.

5. In New Web App Integration:

   • Enter the Name for your new application, for example, Nginx Demo App.

   • Add a URI for the OIDC callback in Sign-in redirect URIs, for example, https://demo.example.com/oidc_callback.

   • Add a URI for post logout redirect in Sign-out redirect URIs, for example, https://demo.example.com/post_logout/.

   • Select Save.

6. In Applications, select Nginx Demo App.

7. In the General tab:

   • Copy the Client ID. You will need it later when configuring NGINX Plus.

   • Copy the Client secret. You will need it later when configuring NGINX Plus.

8. In the Sign On tab:

   • Copy the Okta Issuer (Authorization Server), for example:

     https://dev-123456.oktapreview.com/oauth2/default

     You will need it later when configuring NGINX Plus.

Get the OpenID Connect Discovery URL

Check the OpenID Connect Discovery URL. By default, Okta publishes the .well-known/openid-configuration document at the following address:

https://<okta-domain>/oauth2/default/.well-known/openid-configuration.

1. Run the following curl command in a terminal:

   curl https://dev-123456.okta.com/oauth2/default/.well-known/openid-configuration | jq

   Where:

   • the dev-123456.okta.com is your Okta domain

   • the /oauth2/default is the default authorization server

   • the /.well-known/openid-configuration is the default address for Okta for document location

   • the jq command (optional) is used to format the JSON output for easier reading and requires the jq JSON processor to be installed.

   The configuration metadata is returned in the JSON format:

2. Copy the issuer value, you will need it later when configuring NGINX Plus. Typically, the OpenID Connect Issuer for Okta is https://<okta-domain>/oauth2/default.

Note

You will need the values of Client ID, Client Secret, and Issuer in the next steps.

Assign Users or Groups

By default, Okta might limit application access to certain users or groups. To add or remove users in Okta:

1. Log in to your Okta admin console.

2. In Applications, choose Nginx Demo App.

3. Go to Assignments.

4. Add or remove users and groups that can access this application.

Enable Front-Channel Single Logout (optional)

Front-channel logout allows Okta to notify NGINX Plus when a user signs out of other Single Logout (SLO)-participating applications or from the Okta dashboard itself. Okta sends a front-channel HTTP request (typically loaded in a hidden iframe) to a logout URL that you configure in the application settings.

This feature is optional and requires NGINX Plus Release 36 or later, together with the frontchannel_logout_uri directive in the NGINX OIDC provider configuration.

1. In the Okta Admin Console, go to Settings > Features.

2. Locate Front-channel Single Logout and enable it for your org.

3. Go to Applications > Applications and open your Nginx Demo App (or the OIDC app that you created earlier).

4. On the General tab, click Edit.

5. In the Logout section, under Single Logout, enable User logs out of other logout-initiating apps or Okta. This option enables front-channel SLO for the app.

6. In Logout request URL, enter the NGINX Plus front-channel logout endpoint, for example:

   https://demo.example.com/front_logout

7. Select Include user session details. With this option enabled, Okta includes the user session identifier (sid) and issuer (iss) in the front-channel logout request that it sends to NGINX Plus.

8. Click Save.

Set up NGINX Plus

With Okta configured, you can enable OIDC on NGINX Plus. NGINX Plus serves as the Rely Party (RP) application — a client service that verifies user identity.

1. Ensure that you are using the latest version of NGINX Plus by running the nginx -v command in a terminal:

   nginx -v

   The output should match NGINX Plus Release 36 or later:

   nginx version: nginx/1.29.3 (nginx-plus-r36)

2. Ensure that you have the values of the Client ID, Client Secret, and Issuer obtained during Okta Configuration.

3. In your preferred text editor, open the NGINX configuration file (/etc/nginx/nginx.conf for Linux or /usr/local/etc/nginx/nginx.conf for FreeBSD).

4. In the http {} context, make sure your public DNS resolver is specified with the resolver directive: By default, NGINX Plus re‑resolves DNS records at the frequency specified by time‑to‑live (TTL) in the record, but you can override the TTL value with the valid parameter:

   http {
       resolver 10.0.0.1 ipv4=on valid=300s;
   
       # ...
   }

5. In the http {} context, define the Okta provider named okta by specifying the oidc_provider {} context:

   http {
       resolver 10.0.0.1 ipv4=on valid=300s;
   
       oidc_provider okta {
   
           # ...
   
       }
       # ...
   }

6. In the oidc_provider {} context, specify:

   • your actual Okta Client ID obtained in Okta Configuration with the client_id directive

   • your Client Secret obtained in Okta Configuration with the client_secret directive

   • the Issuer URL obtained in Okta Configuration with the issuer directive

     The issuer is typically your Okta OIDC URL:

     https://dev-123456.okta.com/oauth2/default.

   • The logout_uri is URI that a user visits to start an RP‑initiated logout flow.

   • The post_logout_uri is absolute HTTPS URL where Okta should redirect the user after a successful logout. This value must also be configured in the Okta application’s Sign-out redirect URIs.

   • If the logout_token_hint directive set to on, NGINX Plus sends the user’s ID token as a hint to Okta. This directive is optional, however, if it is omitted the Okta may display an extra confirmation page asking the user to approve the logout request.

   • The frontchannel_logout_uri directive defines the URI that receives OpenID Connect front-channel logout requests from Okta. This URI must be an HTTPS path hosted by NGINX Plus and must match the Front-channel logout URL configured in the Okta application registration. When a front-channel logout GET request is received at this URI (typically in a hidden iframe), the OIDC module clears the local session for the affected user.

   • If the userinfo directive is set to on, NGINX Plus will fetch /oauth2/default/v1/userinfo from the Okta and append the claims from userinfo to the $oidc_claims_ variables.

   • PKCE (Proof Key for Code Exchange) is automatically enabled when the provider metadata advertises the S256 code challenge method in the code_challenge_methods_supported field of the discovery document. You can override this behavior with the pkce directive: set pkce off; to disable PKCE even when S256 is advertised, or pkce on; to force PKCE even if the IdP metadata does not list S256.

   • The module automatically selects the client authentication method for the token endpoint based on the provider metadata token_endpoint_auth_methods_supported. When only client_secret_post is advertised, NGINX Plus uses the client_secret_post method and sends the client credentials in the POST body. When both client_secret_basic and client_secret_post are present, the module prefers HTTP Basic (client_secret_basic).

   • Caution

All interaction with the IdP is secured exclusively over SSL/TLS, so NGINX must trust the certificate presented by the IdP. By default, this trust is validated against your system’s CA bundle (the default CA store for your Linux or FreeBSD distribution). If the IdP’s certificate is not included in the system CA bundle, you can explicitly specify a trusted certificate or chain with the ssl_trusted_certificate directive so that NGINX can validate and trust the IdP’s certificate. :::

```nginx
http {
    resolver 10.0.0.1 ipv4=on valid=300s;

    oidc_provider okta {
        issuer            https://dev-123456.okta.com/oauth2/default;
        client_id         <client_id>;
        client_secret     <client_secret>;
        logout_uri        /logout;
        post_logout_uri   https://demo.example.com/post_logout/;
        logout_token_hint on;
        frontchannel_logout_uri /front_logout;
        userinfo          on;

        # Optional: PKCE configuration. By default, PKCE is automatically
        # enabled when the IdP advertises the S256 code challenge method.
        # pkce on;
    }

    # ...
}
```

7. Make sure you have configured a server that corresponds to demo.example.com, and there is a location that points to your application (see Step 10) at http://127.0.0.1:8080 that is going to be OIDC-protected:

```nginx
http {
    # ...

    server {
        listen      443 ssl;
        server_name demo.example.com;

        ssl_certificate     /etc/ssl/certs/fullchain.pem;
        ssl_certificate_key /etc/ssl/private/key.pem;

        location / {
            # ...

            proxy_pass http://127.0.0.1:8080;
        }
    }
    # ...
}
```

8. Protect this location with Okta OIDC by specifying the auth_oidc directive that will point to the okta configuration specified in the oidc_provider {} context in Step 5:

```nginx
# ...
location / {
     auth_oidc okta;

     # ...

     proxy_pass http://127.0.0.1:8080;
}
# ...
```

9. Pass the OIDC claims as headers to the application (Step 10) with the proxy_set_header directive. These claims are extracted from the ID token returned by Okta:

- [`$oidc_claim_sub`](https://nginx.org/en/docs/http/ngx_http_oidc_module.html#var_oidc_claim_) - a unique `Subject` identifier assigned for each user by Okta

- [`$oidc_claim_email`](https://nginx.org/en/docs/http/ngx_http_oidc_module.html#var_oidc_claim_) the e-mail address of the user

- [`$oidc_claim_name`](https://nginx.org/en/docs/http/ngx_http_oidc_module.html#var_oidc_claim_) - the full name of the user

- any other OIDC claim using the [`$oidc_claim_ `](https://nginx.org/en/docs/http/ngx_http_oidc_module.html#var_oidc_claim_) variable

```nginx
# ...
location / {
     auth_oidc okta;

     proxy_set_header sub   $oidc_claim_sub;
     proxy_set_header email $oidc_claim_email;
     proxy_set_header name  $oidc_claim_name;

     proxy_pass http://127.0.0.1:8080;
}
# ...
```

10. Provide endpoint for completing logout:

```nginx
# ...
location /post_logout/ {
     return 200 "You have been logged out.\n";
     default_type text/plain;
}
# ...
```

11. Create a simple test application referenced by the proxy_pass directive which returns the authenticated user’s full name and email upon successful authentication:

```nginx
# ...
server {
    listen 8080;

    location / {
        return 200 "Hello, $http_name!\nEmail: $http_email\nOkta sub: $http_sub\n";
        default_type text/plain;
    }
}
```

12. Save the NGINX configuration file and reload the configuration:

```nginx
nginx -s reload
```

Complete Example

This configuration example summarizes the steps outlined above. It includes only essential settings such as specifying the DNS resolver, defining the OIDC provider, configuring SSL, and proxying requests to an internal server.

http {
    # Use a public DNS resolver for Issuer discovery, etc.
    resolver 10.0.0.1 ipv4=on valid=300s;

    # Define the OIDC provider block for Okta
    oidc_provider okta {
        # The 'issuer' is your Okta issuer URL
        # For okta dev it looks like: https://dev-123456.okta.com/oauth2/default
        issuer https://dev-123456.okta.com/oauth2/default;

        # Your Okta "Client ID" from the application settings
        client_id <your_client_id>;

        # Your Okta "Client Secret" from the application settings
        client_secret <your_client_secret>;

        # RP‑initiated logout
        logout_uri /logout;
        post_logout_uri https://demo.example.com/post_logout/;
        logout_token_hint on;

        # Front-channel logout (OP‑initiated single sign-out)
        frontchannel_logout_uri /front_logout;

        # Fetch userinfo claims
        userinfo on;

        # Optional: PKCE configuration
        # pkce on;
    }

    server {
        listen 443 ssl;
        server_name demo.example.com;

        ssl_certificate /etc/ssl/certs/fullchain.pem;
        ssl_certificate_key /etc/ssl/private/key.pem;

        location / {
            # Enforce OIDC authentication with Okta
            auth_oidc okta;

            # Pass OIDC claims as HTTP headers to the backend
            proxy_set_header sub $oidc_claim_sub;
            proxy_set_header email $oidc_claim_email;
            proxy_set_header name $oidc_claim_name;

            proxy_pass http://127.0.0.1:8080;
        }

        location /post_logout/ {
            return 200 "You have been logged out.\n";
            default_type text/plain;
        }
    }

    server {
        # Simple test upstream server
        listen 8080;

        location / {
            return 200 "Hello, $http_name!\nEmail: $http_email\nOkta sub: $http_sub\n";
            default_type text/plain;
        }
    }
}

Testing

1. Open https://demo.example.com/ in a browser. You will be automatically redirected to the Okta sign-in page.

2. Enter valid Okta credentials of a user who has access the application. Upon successful sign-in, Okta redirects you back to NGINX Plus, and you will see the proxied application content (for example, “Hello, Jane Doe!”).

3. Navigate to https://demo.example.com/logout. NGINX Plus initiates an RP‑initiated logout; Okta ends the session and redirects back to https://demo.example.com/post_logout/.

4. Refresh https://demo.example.com/ again. You should be redirected to Okta for a fresh sign‑in, proving the session has been terminated.

Note

If you restricted access to a group of users, be sure to select a user who has access to the application.

Legacy njs-based Okta Solution

If you are running NGINX Plus R33 and earlier or if you still need the njs-based solution, refer to the Legacy njs-based Okta Guide for details. The solution uses the nginx-openid-connect GitHub repository and NGINX JavaScript files.

See Also

• NGINX Plus Native OIDC Module Reference documentation

• Release Notes for NGINX Plus R36

Revision History

• Version 3 (November 2025) – Updated for NGINX Plus R36; added front-channel logout support (frontchannel_logout_uri), PKCE configuration (pkce directive), and the client_secret_post token endpoint authentication method.

• Version 2 (August 2025) – Updated for NGINX Plus R35; added RP‑initiated logout (logout_uri, post_logout_uri, logout_token_hint) and userinfo support.

• Version 1 (March 2025) – Initial version (NGINX Plus Release 34).