Article ID: 267910
Article Last Modified on 10/25/2007
APPLIES TO
- Microsoft Exchange Server 2003 Enterprise Edition
- Microsoft Exchange Server 2003 Standard Edition
- Microsoft Exchange 2000 Server Standard Edition
This article was previously published under Q267910
SYMPTOMS
When you use Microsoft Internet Explorer 5 or later to gain access to Microsoft Outlook Web Access (OWA), you may receive the following error message:
However, OWA works when you use a virtual private network (VPN) or a local intranet. Earlier version browsers also work.
CAUSE
This issue can occur because the Hypertext Transfer Protocol (HTTP) 1.1 is used when you use Internet Explorer 5 and later to gain access to OWA, and the HTTP 1.1 protocol is not supported by all firewalls. If the HTTP 1.1 protocol is not supported by the firewall, certain packets from the client are blocked and you receive the error message in the "Symptoms" section of this article.
RESOLUTION
To resolve this issue, implement a firewall solution that supports HTTP 1.1 packets.
WORKAROUND
To work around this issue, do one of the following:
- Implement a SSL connection so that no requests are filtered.
- Modify the firewall so that the firewall passes all HTTP packets regardless of the protocol
- Use an earlier version browser.
MORE INFORMATION
For additional information, click the article numbers below to view the articles in the Microsoft Knowledge Base:
253615 XWEB: Using Browsers Earlier Than Internet Explorer 5 to Gain Access to Outlook Web Access
249557 XWEB: No Option to Gain Access to OWA with Internet Explorer 5 Using Code Path for Earlier Version Browsers
Additional query words: exch2kp2w XWEB
Keywords: kberrmsg kbprb KB267910
