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Configuring IWA on Linux

Integrated Windows Authentication (IWA) is a popular authentication mechanism that is used to authenticate users in Microsoft Windows servers. It uses Negotiate/Kerberos or NTLM to authenticate users based on an encrypted ticket/message passed between a browser and a server. Follow the instructions in the sections below to configure IWA for local or federated authentication in WSO2 Identity Server (IS).

Tip

This IWA authenticator is provided OOTB and was implemented from WSO2 IS 5.3.0 onwards. It uses Kerberos internally and is the recommended approach as it overcomes some limitations of the IWA authenticator provided in previous versions of WSO2 IS which was based on NTLM. If you still want to use the previous IWA authenticator that was based on NTLM, it is available as an extension . For more information on how to setup the NTLM-based IWA authenticator, see Configuring IWA Single-Sign-On.

The benefits of using the authenticator based on Kerberos vs the authenticator based on NTLM are as follows:

  • Can be used on any operating system unlike NTLM which has to be run on a Windows server.
  • Performance and security on Kerberos are better.

Related Links

How IWA with Kerberos works

iwa-wso2

iwa-with-kerberos

Setting up IWA

  1. Add a DNS host entry in the Active Directory (AD) to map the IP address of the WSO2 Identity Server to a hostname. If there are multiple Kerberos domains, WSO2 IS should have a virtual host name for each Kerberos domain.

    Info

    When adding the DNS entry, generally the first part of the hostname is given. The AD will append the rest with its AD domain. For example, if the AD domain is 'wso2.com, after you add a DNS host entry, the final result will be similar to the following:

    idp.wso2.com

    Kerberos does not work with IP addresses, it relies on domain names and correct DNS entries only.

  2. Open the <IS_HOME>/repository/conf/deployment.toml file and add the following configuration.

    [server]
    hostname="idp.wso2.com"
  3. Open the jaas.conf file found in the <IS_HOME>/repository/conf/identity folder and check if the configuration is as follows. (Refer this for more information on JAAS)

    Server {
    com.sun.security.auth.module.Krb5LoginModule required
    useKeyTab=false
    storeKey=true
    useTicketCache=false
    isInitiator=false;
    };
    
    Client {
    com.sun.security.auth.module.Krb5LoginModule required
    useTicketCache=false;
    };
  4. Register WSO2 IS using the same hostname ( idp.wso2.com ) in Active Directory. To do this, use the DNS tool on the machine that is running WSO2 IS to add an entry for the hostname (idp.is.local), and map it to the local IP address.

  5. Create a service account in the Active Directory for WSO2 IS or use an existing account. (For this tutorial, the sample username of the service account is is_linux ).

    Note

    The account used for WSO2 IS needs to be different from the one used by the user to login to the application.

  6. Run the following commands to register WSO2 IS as a service principal in Active Directory.

    Note

    Replace is_linux with the username of your service account in the command below. The format of the command is as follows: [setspn -A HTTP/<url of Identity Server> <service_account>]

    setspn -A HTTP/idp.wso2.com is_linux
    setspn -A HTTP/idp is_linux

You can now set up IWA either as a local authenticator or as a federated authenticator.

Configuring WSO2 IS with IWA as a local or federated authenticator

  1. Follow the steps above to set up IWA.

  2. Start the WSO2 IS server and log in to the management console.

  3. Navigate to Main>Identity Providers and click Add . Enter a name for the identity provider.
  4. Expand the Federated Authenticators section and then expand IWA Federated Configuration .
  5. Fill in the fields as follows:

    Field Description Sample Value
    Enable Enable this to enable a custom authenticator for the identity provider. Selected
    Server Principal Name

    The SPNName should be the SPN you registered in step 6 of Setting up IWA, with the Active Directory domain. The SPNName follows this format:

    For example,

    If the SPN is HTTP/idp.wso2.com , where HTTP is a service class (in this case, HTTP is not the standard protocol; it is the service class) and IS.wso2.com is the Active Directory domain, the SPNName will be HTTP/idp.wso2.com@wso2.com

    HTTP/idp.wso2.com@wso2.com
    Server Principal Password The SPNPassword should be the password of the service account associated with the SPN (the service account created in step 6 of Setting up IWA ). -
    User store domains

    [Mandatory only if you want to use IWA as a local authenticator]

    The mounted user stores in which you want the user’s existence to be checked in.

    • To configure IWA as a local authenticator , mount the user store domain names of the relevant user stores that you expect the user to be in.
    • To configure IWA as a federated authenticator , leave this field blank.
    PRIMARY

    • IWA as a Local Authenticator iwa-as-a-local-authenticator

    • IWA as a Federated Authenticator iwa-as-a-federated-authenticator

  6. Configure your browser to support Kerberos and NTLM. The points below explain how to configure each browser.

    Configuring firefox

    1. Type about:config in the address bar, ignore the warning and continue, this will display the advanced settings of Firefox.

    2. In the search bar, search for the key " network.negotiate-auth.trusted-uris.

    configuring-firefox-for-kerberos

    3. Add the WSO2 Identity Server URL and click OK.

    adding-wso2-is-url

    Configuring Internet Explorer/Chrome

    1. Go to Tools ->Internet Options.

    2. In the “security” tab select local intranet.

    configuring-internet-explorer-chrome

    3. Click the Sites button. Then add the URL of WSO2 Identity Server there.

    adding-wso2-is-url-ie-chrome

    Chrome simply inherits the settings from Internet Explorer. So you don’t have to configure anything additionally.

Testing the IWA authenticator

  1. Set up IWA as a local authenticator or as a federated authenticator by following the steps above.
  2. Download and set up the Travelocity sample application. To do this, follow the instructions on the Deploying the Sample Applications page.

  3. Edit the service provider you created for the Travelocity sample, and expand the Local and Outbound Authentication section.

  4. Select Federated Authentication as the Authentication Type and select the identity provider you created above.

  5. Restart the Apache Tomcat server and run the Travelocity sample application from a Windows machine.

Troubleshooting Tips

  • Use hostnames only (no IP addresses).
  • Check the configuration of the jaas.conf file, particularly the isInitiator=false property under the Server section (see step 3 of the Setting Up IWA section).
  • Make sure that your service principal (IS) is associated with only one account.

  • If you get an exception with an error message similar to “Checksum failed”, check whether you have given the correct password.

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