Microsoft KB Archive/293427

= Error Message: Page Cannot Be Displayed =

Article ID: 293427

Article Last Modified on 1/18/2006

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APPLIES TO


 * Microsoft Small Business Server 2000 Standard Edition
 * Microsoft BackOffice Server 2000
 * Microsoft Internet Security and Acceleration Server 2000 Standard Edition

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This article was previously published under Q293427



SYMPTOMS
When you attempt to connect to a Web site on the Internet by using either the Firewall or secure network address translation (SecureNAT) client, you may receive the following error message:

Page cannot be displayed.



CAUSE
This behavior can occur because, by default, Microsoft Internet Security and Acceleration (ISA) Server on Small Business Server 2000 and BackOffice Server 2000 is not configured to enable Firewall and SecureNAT client computers to access Web sites.

The Hypertext Transfer Protocol (HTTP) redirector filter is used to enable both SecureNAT and Firewall clients access to the Web Proxy service in the cache. This program filter searches for HTTP requests and if the filter finds a request in the data stream, the filter captures the request, and then redirects it to the Web Proxy service so that the requests can use the cache.

When the HTTP redirector filter sends the requests to the Web Proxy service, the filter removes all user and domain information. If the requests do not meet the requirements of the Access rules, the requests are denied.



WORKAROUND
To work around this behavior, create a protocol definition for SecureNAT and Firewall clients:
 * 1) Click Start, point to Programs, click Microsoft ISA Server, and then click ISA Management.
 * 2) On the View menu, click TaskPad.
 * 3) Expand Servers and Arrays.
 * 4) Expand  , expand Access Policy, and then click Protocol Rules.
 * 5) In the right pane, click Create a Protocol Rule for Internet Access to open the New Protocol Rule Wizard.
 * 6) Type a name for the rule, and then click Next.
 * 7) Disable any protocols that you want to exclude from the Protocols rule, and then click Next. (By default, all of the Internet protocols that are serviced by the Web Proxy service are selected.)
 * 8) Select when the Schedule rule must be applied (by default, &quot;Always&quot; is selected), and then click Next.
 * 9) Under Client Type, click Specific Computers (client address sets), and then click Next.
 * 10) Under Client Sets, click Add to add a Client Set.
 * 11) On the Add Client Sets window, click New.
 * 12) On the Client Set window, name the Client Set, and then click Add.
 * 13) On the Add/Edit IP Addresses window, enter the range of Internet Protocol (IP) addresses for the clients that are going to make these requests, and then click OK twice.
 * 14) When the new Client Set is displayed in the &quot;Include these sets:&quot; field, click OK to close the Add Client Sets window.
 * 15) When the Client Set that you created is displayed in the &quot;Client Sets&quot; field, click Next.
 * 16) Click Finish to complete the wizard.

This Protocol rule can enable browser requests from both Firewall and SecureNAT clients in the IP range that had been previously specified and enable both of these clients to access the Internet.

NOTE: You may have to close and re-open Internet Explorer on the client for the new Protocol rule to take effect.



STATUS
This behavior is by design.



MORE INFORMATION
By default, both BackOffice Server 2000 and Small Business Server 2000 create two Access rules for users. Any requests that do not meet the requirements of these rules are denied. These rules are:
 * The Site and Content rule, known as the BackOffice Internet Access Site and Content rule, enables users that belong to the BackOffice Internet Users group to access any external destination.
 * The Protocol rule, known as the BackOffice Internet Access Protocol Rule, enables all IP traffic to go through ISA Server for the users that belong to the BackOffice Internet Users group.

Additional query words: smallbiz sbs

Keywords: kberrmsg kbnetwork kbprb KB293427

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