When you try to re-authenticate the OWA client on the forms-based authentication page, you may receive an "Unknown Request" error message in ISA Server 2004

You publish a Microsoft Exchange Server 2003 Outlook Web Access (OWA) server that uses forms-based authentication in Microsoft Internet Security and Acceleration (ISA) Server 2004. When you try to re-authenticate the OWA client on the forms-based authentication page, you may receive the following error message:

This problem occurs if the following conditions are true:

• You configure a Web listener in ISA Server 2004 to use OWA forms-based authentication.
• The forms-based authentication cookie has expired on the OWA client.

When you try to re-authenticate the OWA client on the forms-based authentication page, the error message occurs. However, after the OWA client updates the Web page, the authentication process is successful.

Note See the "More Information" section for information about how to enable OWA forms-based authentication in ISA Server 2004 and how to specify a time-out value for a forms-based authentication cookie.

Service pack information

To resolve this problem, obtain the latest service pack for Internet Security and Acceleration Server 2004. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Hotfix Information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

ISA Server 2004 Service Pack 1.

For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Restart requirement

You do not have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. This problem was first corrected in Internet Security and Acceleration Server 2004 Service Pack 2.

To enable OWA forms-based authentication for a Web publishing rule in ISA Server 2004, follow these steps:

1. Use an account that has administrative credentials to log on to the computer that is running ISA Server 2004.
2. Click Start, point to Programs, point to Microsoft ISA Server, and then click ISA Server Management.
3. In the left pane, expand the server name, and then click Firewall Policy.
4. In the right pane, right-click the Web publishing rule that you want to configure, and then click Properties.
5. In the Web publishing rule properties dialog box, click the Listener tab.
6. In the This rule applies to requests received on the following listener list, click the listener, and then click Properties.
7. In the listener properties dialog box, click the Preferences tab, and then click Authentication.
8. Click to select the OWA Forms-Based check box.
9. Click OK three times.

To configure a time-out value for an OWA forms-based authentication cookie in ISA Server 2004, follow these steps:

1. Click Start, point to Programs, point to Microsoft ISA Server, and then click ISA Server Management.
2. In the left pane, expand the ISA Server computer name, and then click Firewall Policy.
3. In the right pane, right-click the Web publishing rule that you want to configure, and then click Properties.
4. In the Web publishing rule properties dialog box, click the Listener tab.
5. In the listener properties dialog box, click the Preferences tab, and then click Authentication.
6. Click Configure next to Configure OWA forms-based authentication.
7. Set the time-out value that you want next to Client on public machines.
8. Click OK four times.