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Solution: Exchange 2010 OWA Redirection Problem for Exchange 2007 Mailboxes

Exchange 2010 (SP1) OWA Redirection Problem for Exchange 2007 with Form based Authentication Disabled

Recently I found out that there is a bug in Exchange 2010 SP1 that when you disable Form based Authentication on Exchange 2010 CAS OWA V.D., and want the user to use their Integrated Windows Credentials to directly logged into OWA, but since Form based Authentication is disabled, and users mailboxes are on Exchange 2010 Mailbox Server, so Exchange 2010 OWA instead of silently redirect request to Exchange 2007 OWA, it provides the link to user that for optimal performance you should access your mailbox on this URL, which actually breaks the redirection b/w Exchange 2010 OWA and Exchange 2007 OWA.

Cause:

This is a known issue in Exchange 2007 SP1 that if the form based authentication is disabled on Exchange 2010 CAS (OWA), Exchange 2010 will not saliently redirect the OWA request for Exchange 2007 Mailbox users.

Resolution:

For making this work, we have to modify the below configuration file in Exchange 2010 SP1 CAS Server, so it will silently redirect the user request from Exchange 2010 to Exchange 2007:

Open below file in notepad:
C:\Program Files\Microsoft\Exchange Server\V14\ClientAccess\OWA\ casredirect.aspx

And add the below parameter in the file, as mentioned below:
<%
Response.Redirect(RedirectionUrl);
%>

between the tags

<body class=”owaLgnBdy<%=IsRtl ? ” rtl” : “”%>”>
<table align=”center” id=”tblMain” cellpadding=0 cellspacing=0>

So it will look like below in the notepad:

<body class=”owaLgnBdy<%=IsRtl ? ” rtl” : “”%>”>
<%
Response.Redirect(RedirectionUrl);
%>
<table align=”center” id=”tblMain” cellpadding=0 cellspacing=0>

I hope this solution will solve your problem, and will make your transition smother.

Cheers!

Zahir Hussain Shah
Infrastructure Practice Consultant – Unified Communications
MCSE, MCTS, MCTIP Enterprise Administrator, CCNA, ITIL
Blog: http://zahirshahblog.com | LinkedIn | Twitter

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2 responses to “Solution: Exchange 2010 OWA Redirection Problem for Exchange 2007 Mailboxes”

  1. sajid

    hey…
    is there an easy way to do that.. i did not understand completely what your are trying to say..

  2. Zahir Hussain Shah

    Tell me what you didn’t understood, by the way, do you have the same problem?

    This problem I saw in Exchange Server 2010 SP1 RTM release, and this solution is used to fix the problem, where I was not using the Exchange Form based authentication on Exchange 2010 CAS Servers, and on both Exchange 2007 and Exchange 2010 CAS OWA I was using Windows Integrated Authentication, to make my Exchange OWA Authentication single-sign-on.

    I would recommend to go with Exchange 2010 SP2 installation, and see whether it fixes your problem or not for co-existing of Exchange 2010 OWA with Exchange 2007 OWA.

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