How to configure host header and authentication information in Exchange 2000 Server or Exchange Server 2003 Outlook Web Access on a Windows Server 2003 or Windows 2000 server cluster

This article describes how to configure host header and authentication information on a computer that is running Microsoft Exchange Server 2003 or Microsoft Exchange 2000 Server and that uses Microsoft Outlook Web Access (OWA) on a server cluster that is based on one of the following operating systems:

• Microsoft Windows Server 2003
• Microsoft Windows 2000 Server

When you use the cluster service on a computer that is running Exchange 2003 or Exchange 2000, and when Exchange is configured to use OWA, the Exchange computer creates a virtual Internet Information Services (IIS) Server instance. This means that one IIS Server instance is created for each Exchange computer instance. By default, the OWA instance is configured to use basic authentication to which no default domain or realm is specified. Additionally, the OWA instance is configured to use Integrated Windows authentication as the authentication method and the network name of the Virtual Exchange Server Instances as a host header.

When back-end servers are clustered, you must add host headers for every possible method that users may use to try to connect to OWA. These host headers may include the following:

• NetBIOS names
• Name of the front-end server
• Internal IP address of the front-end server
• Fully-qualified domain name of the front-end server
• External URL
• External IP address

If the network environment requires that you change the authentication method or the host header name (for example, by adding the fully qualified domain name [FQDN] of your DNS record) you must make these changes by using the Exchange System Manager program and not by using the Internet Information Services (IIS) Manager program. If you apply the changes in the Internet Information Services snap-in, Exchange resets the changes to use the configurations that are set in the Exchange System Manager program. This functionality is an update process that is handled by directory service to metabase.

Note: Because the host header is set to the Exchange computer virtual network name by default, you are only able to access the site by that network name. If you try to access the site by an FQDN, you receive one of the following error messages until you modify the host header information: To change the host header information, follow these steps:

1. Start Exchange System Manager.
2. Expand Servers, expand the appropriate server name, expand Protocols, and then expand HTTP.
   
   Note You may have to expand the virtual server to obtain this option.
3. Right-click Exchange Virtual Server, and then click Properties.
4. Click Advanced that is located to the right of the IP Addresslist, and then click Add.
5. Verify the IP address and port numbers, set the IP address and port numbers correctly, and then type the FQDN, or the appropriate host header information, in the Host Header box.
   
   Note Do not remove the host header name that currently exists, for example, the Exchange Server computer virtual net name. Exchange Server Cluster Services requires that a specific virtual server name be in the host header field.
6. Click OK two time, click Apply, and then click OK.

To change the Authentication Method on the virtual server level:

1. Start Exchange System Manager.
2. Expand Servers, click the appropriate server name, expand Protocols, and then click HTTP.
3. Right-click Exchange Virtual Server, and then click Properties.
4. Click the Access tab, and then click Authentication.
5. Apply the same changes that you applied in the Internet Information Services snap-in. If you want to specify a default domain for authentication, type the default domain name (the NetBIOS name) in the Default Domain dialog box.
6. Click OK two times.

To make changes to the authentication method on the virtual folder level:

1. Start Exchange System Manager.
2. Expand Servers, click the appropriate server name, click to expand Protocols, click HTTP, and then click Exchange Virtual Server.
3. Right-click the virtual folder that requires changes, and then click Properties.
4. Click the Access tab, and then click Authentication.
5. Apply the same changes that you applied in the Internet Information Services snap-in. If you want to specify a default domain for authentication, type the default domain name (the NetBIOS name) in the Default Domain box.
   
   Note In Exchange 2003, type the NetBIOS name of your domain in the Default domain box.
6. Click OK two times.