We have exchange 2007, using cas-proxy to establish owa link. When user is member of many groups (more then 500) logging on is not possible in OWA 2007. When logging in directly via /OWA works. (we also see header too long error in firefox not IEx)Anyone idee ?

Are there any relevant events on either CAS server?Active Directory, 4th Edition - www.briandesmond.com/ad4/

With Exchange 2003 you would change the HTTP MaxFieldLength and MaxRequestBytes to 32768 (decimal). Not sure it this applies to Exchange 2007 as well. Error message when an Outlook Web Access user tries to access a mailbox in Exchange Server 2003: “HTTP 400 Bad Request (Request header too long)”http://support.microsoft.com/kb/920862 IIS 6.0 MaxFieldLength parameter not set correctlyhttp://technet.microsoft.com/en-us/library/aa996475%28EXCHG.80%29.aspxMCTS: Messaging | MCSE: S+M | Small Business Specialist

Hello Jon-Alfred,These parameters were also already changed, and no efect. We are running Windows 2008 SP2 as OS.

Brian, no errors on CAS HT DC CMS servers. Also de logging off IIS on several servers looks normal.

Hi Peter, For the suggestions in KB920862, please make sure you have changed the registry key in both CAS servers and mailbox servers where user's mailbox lives. I saw similar issue is fixed by following this KB in Exchange 2007 in our internal knowledge base. Please backup your registry before this change. Meanwhile, I suggest you upgrade your Exchange to the latest version and check the issue again. The latest patch is Update Rollup 2 for Exchange Server 2007 Service Pack 2: http://www.microsoft.com/downloads/details.aspx?FamilyID=fa83be11-9d5e-47bc-9a51-a10986f22928&displaylang=en Thanks, Elvis

I have also this problem.I have made the registry settings within IIS 7 on Windows 2008 X64 Sp2.Our Exchange Version is 2007 SP1 RU 9.If we use /owa it works on kerberos but with /exchange we see the bad request error on the mailbox servers.I am currently in touch with microsoft for this problem because the reg keys wil not work (set them only on mailbox server because of the /exchange redirect)Note we have this also on IIS 7 on a Enterprise Vault Server. And the reg keys wil not be picked up.We used this article.http://technet.microsoft.com/en-us/library/dd159912(EXCHG.80).aspx

Hi Peter,Any update on the issue?Hi mweber1980,Do you have any update from our CSS for the issue?