XWEB: WWW Service Crash Causes Server Unavailable Errors with WLBS (226382)

SUMMARY

When you are connected with a browser to an Outlook Web Access (OWA) server, the following error messages may be displayed if this server is also a part of a cluster of Windows Load Balancing Servers (WLBS), and the WWW publishing service has stopped:

Sorry! The Microsoft Exchange Server is down or the HTTP service has been disabled by an administrator. Please try your request again later.

-or-

HTTP/1.0 404 Object Not Found

-or-

The browser screen may be displayed as a white screen and the browser may also display an error similar to the following:

Host Not Found

-or-

This page cannot be displayed.

MORE INFORMATION

You may get the above error messages if the WWW service has failed on the server your client is connected to. After the service fails, you will be unable to connect to your Exchange Server computer using the OWA component. Even though the OWA server is a part of a WLBS cluster, the WLBS service is not aware that the service has stopped, and therefore, cannot redirect you to another on-line server. To use OWA to access your Exchange mailbox, you will have to close the browser and start again in order to connect to another OWA server.

In version 2.2 for Windows NT 4.0, WLBS does not include application monitoring tools or features. Many leading monitoring tools on the market can be easily configured by an end-user to provide this support by creating an alert option specifically for WLBS. In the alert functions of many monitoring tools, an option is provided for running a script in addition to the standard "Page this number" or "E-mail this address" options. Using these scripts, WLBS can be tied into the existing monitoring infrastructure.

For example, if the Internet Information Service (IIS) application on Server A does not respond for X seconds, then run the following script:

'wlbs stop (cluster IP address):(Server A's host ID or dedicated IP address)

Some examples of third-party tools:

SiteScope by Freshwater Software (http://www.freshtech.com)
AppManager by NetIQ (http://www.netiq.com)
WhatsUp Gold by Ipswitch

The third-party products that are discussed in this article are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, regarding the performance or reliability of these products.