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Upgrading to Exchange 2010 OWA

Medium Priority
Last Modified: 2012-05-11
Hi Experts

I've poured over the literature regarding upgrading from Exchange 2003 to 2010, and have a fair idea, however I have a question which seems not to be covered :-

What is my best route to follow, if I want to replace my existing OWA with a 2010 OWA ?
In other words, the old OWA and new OWA will not run together - old one is to be killed off before AD prep . . .

All the sites mention using DNS entries for legacy.place.com as well as current.place.com

Does this fall away for only having a new 2010 OWA, and my clients will then run through 2010 OWA to either the Exchange 2003 or 2010 mailboxes, on our existing owa.place.com address ?  Our mailbox migration will take a while, so I need both to co-exist . . .

Thanks in advance !
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Rajith EnchiparambilOffice 365 & Exchange Architect

You need both entries 2003owa.domain.com and 2010owa.domain.com in the SAN cert if you need co-existence.

So, if ur current owa is 2003owa.domain.com, add that as well when you buy SAN cert for 2010 in addition to the new owa url.


Ah ok, so that is independant of the actual existence of the OWA itself ?  
Meaning I can shut down the 2003OWA box and install the 2010OWA as long as I have the entries in DNS ?
Rajith EnchiparambilOffice 365 & Exchange Architect

No, you need to keep both 2003 and 2010 servers up and running.

You reconfigure your firewall so that all OWA points to 2010 CAS servers. WHen the mailbox is on 2010 mailbox server, 2010 CAS will serve the user directly. When the mailbox is on 2003 server, 2010 CAS will redirect the request to your 2003 server who will then serve the user.

In order that there is no certificate issues, we have both 2003owa and 2010owa urls in the SAN cert on 2010 CAS servers. The cert containing 2003owa url should be present on 2003 exchange as well.


Right, I did see this posting before. Thank you.

If I install the 2010OWA with the 2003OWA down, is it as simple as bringing the 2003OWA back up and setting the links accordingly ?

This assumes that the AD prep and Schema prep happens happily . . .
Rajith EnchiparambilOffice 365 & Exchange Architect

You dont have to do anything to 2003OWA. Install 2010 CAS servers and tweak the urls later. Both 2003 and 2010 OWA can co-exist happily, no need to bring any down.


Lovely. Thanks

Another question to play devli's advocate !

If I don't need anyone to access their 2003 mailbox via OWA, and I migrate those that need OWA to 2010, will I still need the 2003OWA box ?

I'm thinking of only having my old Exchange 2003 box with the OWA2010 and 2 Exchange 2010 boxes in DAG . . .
Rajith EnchiparambilOffice 365 & Exchange Architect

Your old 2003 server will not be able to serve Exchange 2010. You will need 2010 CAS servers.

If you only have 2 exchange 2010 servers in a DAG, then u need to install CAS & HUB as well on those servers and use hardware or software load balancing for CAS/HUB load balancing.


Ok, as I said, I will have :-

1 x Exchange 2003 with existing mailboxes
1 x Exchange 2010 OWA/CAS + HUB
2 x Exchange 2010 Mailbox in DAG

Following the link you posted earlier, I can then transition the 2003 mailboxes to 2010 and remove the old 2003 server once done.

If anyone wants to access OWA, they will have to wait until they are migrated to 2010 - yes ?
Office 365 & Exchange Architect
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Many thanks for all your help. As it happens, we are able to run with :-
1 x 2003 Exchange
1 x 2010 OWA/CAS + HUB
1 x 2010 MB + HUB + DAG
1 x 2010 MB + CAS + DAG

Our 2003 users do not have access via OWA 2003, but when they are migrated to 2010, they have access via OWA 2010.

All is looking good and migration continues . . . 2010 is very powerful and very flexible !


Oh yes, and the existing 2003 users are all still able to communicate via 2003.
They can also communicate with those who are now on 2010 and visa versa.
We are migrating those that need OWA first, to 2010 and the rest will be migrated in time.
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