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Using a different authentication database

Updated: January 21, 2005

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

Using a different authentication database

This topic describes how IAS can be used as a RADIUS proxy to forward RADIUS messages between access servers and two different user account databases. An Active Directory forest and another user account database are used as examples.

The following configuration is for an organization that uses:

  • Active Directory domains.

    Active Directory domains contain the user accounts, passwords, and dial-in properties that each IAS server requires to authenticate user credentials and evaluate both authorization and connection constraints. To optimize IAS authentication and authorization response times and minimize network traffic, IAS is installed on domain controllers.

  • Another user account database.

    There is another user account database that is used to authenticate and authorize connection attempts. Examples of other user account databases are Novell Directory Services (NDS) and Structured Query Language (SQL). Because IAS can only access Windows-based user account databases, a third-party RADIUS server must be used to access another user account database.

  • Two IAS servers for each authentication database.

    Two IAS servers (one primary and one secondary) are used to provide fault tolerance for RADIUS-based authentication, authorization, and accounting for each user account database. If only one RADIUS server is configured and it becomes unavailable, access clients for that user account database cannot connect. By using two IAS servers and configuring the IAS proxies for both primary and secondary IAS servers for each account database, the IAS proxies can detect when the primary RADIUS server is unavailable and automatically fail over to the secondary IAS server.

  • Remote access policies.

    Remote access policies are configured to specify, based on group membership, the different types of connection constraints for users.

  • Two IAS proxies.

    Two IAS proxies are used to provide fault tolerance for RADIUS requests that are sent from access servers.

The following illustration shows the use of IAS proxies to forward RADIUS messages between the access servers and the RADIUS servers that are accessing two different user account databases.

Wireless access

Note

  • This topic only describes how to configure IAS. It does not describe the configuration of Active Directory domains, access servers, the third-party RADIUS servers, or the other user account database. For more information about how to deploy these components, see the appropriate Help topics.

To configure IAS for this example, complete the following steps:

  • Configure the Active Directory forest for user accounts and groups.

  • Configure the primary IAS server on a domain controller.

  • Configure the secondary IAS server on a different domain controller.

  • Configure the primary and secondary RADIUS servers for the other user account database.

  • Configure the primary IAS proxy.

  • Configure the secondary IAS proxy.

  • Configure RADIUS authentication and accounting on the access servers.

Configuring the forests for user accounts and groups

To configure the forest for user accounts and groups, do the following:

  1. Ensure that all users that are making network access connections have a corresponding user account.

  2. Manage your network access by group by setting the remote access permission on user accounts to Control access through Remote Access Policy. For more information, see Configure remote access permission for a user.

  3. Organize your remote access users into the appropriate universal and nested groups in order to take advantage of group-based remote access policies. For more information, see Group scope.

  4. If you are using the Challenge-Handshake Authentication Protocol (CHAP), enable support for reversibly encrypted passwords for the appropriate domains. For more information, see Enable reversibly encrypted passwords in a domain.

Configuring the primary IAS server on a domain controller

To configure the primary IAS server on a domain controller, do the following:

  1. On the domain controller, install IAS as an optional networking component. For more information, see Install IAS.

  2. Configure the IAS server computer (the domain controller) to read the properties of user accounts in the domain. For more information, see Enable the IAS server to read user accounts in Active Directory.

  3. If the IAS server authenticates connection attempts for user accounts in other domains, verify that the other domains have a two-way trust with the domain in which the IAS server computer is a member. Next, configure the IAS server computer to read the properties of user accounts in other domains. For more information, see Enable the IAS server to read user accounts in Active Directory. For more information about trust relationships, see Trust direction.

    If the IAS server authenticates connection attempts for user accounts in other domains, and those domains do not have a two-way trust with the domain in which the IAS server computer is a member, see Authentication across forests.

  4. Enable file logging for accounting and authentication events. For more information, see Configure log file properties.

  5. Add the IAS proxies as RADIUS clients of the IAS server. For more information, see Add RADIUS clients. Verify that you are configuring the correct name or IP address and shared secrets. For more information, see Shared secrets.

  6. Create the appropriate remote access policies for access clients.

    For examples of remote access policies, see Remote Access Policies Examples.

Configuring the secondary IAS server on a different domain controller

To configure the secondary IAS server on a different domain controller, do the following:

  1. On the other domain controller, install IAS as an optional networking component. For more information, see Install IAS.

  2. Configure the secondary IAS server computer (the other domain controller) to read the properties of user accounts in the domain. For more information, see Enable the IAS server to read user accounts in Active Directory.

  3. If the secondary IAS server authenticates connection attempts for user accounts in other domains, verify that the other domains have a two-way trust with the domain in which the secondary IAS server computer is a member. Next, configure the secondary IAS server computer to read the properties of user accounts in other domains. For more information, see Enable the IAS server to read user accounts in Active Directory. For more information about trust relationships, see Trust direction.

    If the secondary IAS server authenticates connection attempts for user accounts in other domains, and those domains do not have a two-way trust with the domain in which the IAS server computer is a member, see Authentication across forests.

  4. Copy the configuration of the primary IAS server to the secondary IAS server. For more information, see Copy the IAS configuration to another server.

Configuring the primary and secondary RADIUS servers for the other user account database

To configure the primary and secondary RADIUS servers to access the additional user account database and to add the two IAS proxies as RADIUS clients, see the documentation for the RADIUS servers.

Configuring the primary IAS proxy

To configure the primary IAS proxy, do the following:

  1. On a computer running Windows Server 2003, Standard Edition; Windows Server 2003, Enterprise Edition; or Windows Server 2003, Datacenter Edition; install IAS as an optional networking component. For more information, see Install IAS. The computer on which IAS is installed is not required to be dedicated to forwarding RADIUS messages. For example, you can install IAS on a Web server, file server, or DNS server.

  2. If needed, configure additional UDP ports for RADIUS messages that are sent by the access servers. For more information, see Configure IAS port information. By default, IAS uses UDP ports 1812 and 1645 for authentication and ports 1813 and 1646 for accounting.

  3. Add the access servers as RADIUS clients of the IAS server. For more information, see Add RADIUS clients. Verify that you are configuring the correct name or IP address and shared secrets. For more information, see Shared secrets.

  4. Create a connection request policy that forwards RADIUS request messages to the IAS servers where the realm name matches the user accounts in the forest.

    Use the New Connection Request Policy Wizard to create a connection request policy that forwards connection requests to a remote RADIUS server group and where the realm name matches the realm name for the user accounts in the forest. Clear the check box that removes the realm name for authentication. In the New Connection Request Policy Wizard, use the New Remote RADIUS server Group Wizard to create a remote RADIUS server group with members that include the two IAS servers.

    For more information, see Add a connection request policy.

  5. Create a connection request policy that forwards RADIUS request messages based on the realm name of accounts in the additional user account database to the RADIUS servers.

    Use the New Connection Request Policy Wizard to create a connection request policy that forwards connection requests to a remote RADIUS server and where the realm name matches the realm name for the user accounts in the additional user account database. Clear the check box that removes the realm name for authentication. In the New Connection Request Policy Wizard, use the New Remote RADIUS server Group Wizard to create a remote RADIUS server group with members that include the two RADIUS servers.

    For more information, see Add a connection request policy.

  6. Delete the default connection request policy named Use Windows authentication for all users. For more information, see Delete a connection request policy.

Configuring the secondary IAS proxy

To configure the secondary IAS proxy on another computer, do the following:

  1. On another computer running Windows Server 2003, Standard Edition; Windows Server 2003, Enterprise Edition; or Windows Server 2003, Datacenter Edition; install IAS as an optional networking component. For more information, see Install IAS.

  2. Copy the configuration of the primary IAS proxy to the secondary IAS proxy. For more information, see Copy the IAS configuration to another server.

Configuring RADIUS authentication and accounting on the access servers

To configure each access server to use the primary and secondary IAS proxies for the authentication, authorization, and accounting of network connections, do the following:

  1. If the dial-up or VPN server is a computer running Windows Server 2003, Standard Edition; Windows Server 2003, Enterprise Edition; Windows Server 2003, Datacenter Edition; or Windows 2000 and the Routing and Remote Access service, configure the primary and secondary IAS proxies as RADIUS servers for both RADIUS authentication and accounting. For more information, see Use RADIUS authentication and Use RADIUS accounting.

  2. If the dial-up or VPN server is a computer running Windows NT server 4.0 and the Routing and Remote Access Service (RRAS), see the Windows NT server 4.0 online Help for information about how to configure the primary and secondary IAS proxies as RADIUS servers for RADIUS authentication.

  3. If the dial-up server, VPN server, wireless access point, or authenticating switch is a third-party access server, see the documentation for the access server to determine how to configure it as a RADIUS client with two RADIUS servers (the primary and secondary IAS proxies).

Note

  • You can configure IAS in Windows Server 2003, Standard Edition, with a maximum of 50 RADIUS clients and a maximum of 2 remote RADIUS server groups. You can define a RADIUS client using a fully qualified domain name or an IP address, but you cannot define groups of RADIUS clients by specifying an IP address range. If the fully qualified domain name of a RADIUS client resolves to multiple IP addresses, the IAS server uses the first IP address returned in the DNS query. With IAS in Windows Server 2003, Enterprise Edition, and Windows Server 2003, Datacenter Edition, you can configure an unlimited number of RADIUS clients and remote RADIUS server groups. In addition, you can configure RADIUS clients by specifying an IP address range.

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