OWA pointing to 2 backend servers

Running Exchange 2003.  We have one front end server and two backend active/passive clusters - how can I point OWA to both backends so all users on both exchange servers can use OWA.  At the moment only users on the first backend can use OWA.
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this is not normal. You don't define a specific Back-End server on a Front-End server. It finds the back-End server based on the login information of the user logging on.

Are the two Back-End server part of the same administrative group in Exchange 2003? You should check the eventlogs on the Front-End server and the backend server that is not accessible for any clues and post them here.

best regards,
mrsmileynsAuthor Commented:
My coworker used a case we had already open with M$ to get some new info - it seems the front end and old backend are 2003 SP1, but the new cluster that we built is SP2 - M$ said that is why it is not working.
That can be correct, there is a workaround for making a SP1 front-end work on a SP2 backend, but then again you will not be able to open mailboxes on the SP1 backend. the workaround involves replacing soem of the ASP Pages used by OWA

My advise: upgrade the old backend to SP2, before updating the front-end to SP2. Take into consideration that your frontend will not run in SP2 if you have more than 1000 information stores in your Exchange organisation. You will need an additional fix from M$ then. We have this issue and are still running our frontends in SP1 although every backend is running SP2.

You can read all about fronten-backend topolgy in the following article:

Upgrading the old backend to SP2 should not be that hard of a problem:
1. install Exchange 2003 SP2 on the passive node of the cluster
2. failover the Exchange Virtual server to tha passive node and right-click the Exchange System Attendant in CLuster Administrator. It shoulds say Upgrade to Service Pack 2
3. install Exchange Service Pack 2 on the other node, now the passive one

best regards,


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The basic rule with a frontend / backend scenario is that the frontend should always be higher or equal to the backends that it is serving. You should always update the frontend first.
This also has the advantage of giving you an opportunity to see whether a new service pack works for you or not. A frontend server is easier to replace than the backend.

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