Confused about Licensing for CAS

  • Thread starter Pantherfan
  • Start date Views 662


I am planning on a highly available exchange 2010 environment consisting of 2 mailbox servers in a dag with 16 databases, and 2 CAS/HUB servers in a cas array using WNLB. I am confused on licensing though.
For the CAS servers, can i purchase standard edition exchange and windows server licenses? I plan on running R2, and I i hear that WNLB is now included on standard edition. I know I need enterprise for the mailbox servers due to the # of databases, but the CAS/HUB licenses are confusing me..

Jonas Andersson [MCITP]


Yes you can use Standard edition for CAS/HUB servers, there's no need for enterprise on them.
And it's true, WNLB is included in Windows std edt..

Just make sure that you use Windows Enterprise for your MBX servers if you plan to use D.A.G.
Jonas Andersson MCTS: Microsoft Exchange Server 2010, Configuration | MCITP: EMA | MCSE/MCSA Blog:


Thank you very much for this answer. Exactly what I was looking for as well.

One other question, does this apply to other roles as well (edge and unified messaging?)

I basically want to have the following:
2x Edge 2xCAS/HUB (two roles, same boxes) 3x MB 2x UM
All my CALS are enterprise so that isn't my worry.



Mike Crowley

Exchange Enterprise CALs are required IN ADDITION TO Standard CALs for use of advanced features like journaling on Archive mailboxes. CALs are different than Exchange server licenses. Which are also different than Windows server licenses, which are also different than Windows CALs :) Each of these servers you list can run in either Standard or Enterprise versions. The benefit of the Enterprise version of Exchange applies to Mailbox Servers. Enterprise Edition can scale to 100 databases per server; Standard Edition is limited to 5 databases per server.

On-Premise Licensing for Exchange Server 2010

Mike Crowley
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Thanks Mike.

As I understand it then, I really only need to have my mailbox servers as E2k10 and Win2k08 Enterprise to support more than 5 mailboxes and in a DAG config, all my other roles are safe being standard version (which is great from a cost perspective).

Again, thanks very much.



That was also very helpful Jonas. It amazes me how often I cruise the MS site looking for information and overlooked this one page.


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