I'm confused with NLB configuration on Hyper-V 2008 R2. 1. Does NLB requires different subnets for configurations? if so, 2. How do you make vNIC1 from VM1 on Hyper-V1 to talk to vNIC1 from VM1 on Hyper-V2? If not (for case 1), then I would put all vNIC and Virtual Cluster IP on the same subnet as my LAN. Correct? Thanks Kris

NLB does not require different subnets. However you may have run into an issue described here: Uncovering the new RPC Client Access Service in Exchange 2010 (Part 3) http://www.msexchange.org/articles_tutorials/exchange-server-2007/planning-architecture/uncovering-new-rpc-client-access-service-exchange-2010-part3.html While this is Exchange 2010, the NLB / Hyper-V problem applies to Exchange 2007 as well. MCTS: Messaging | MCSE: S+M | Small Business Specialist

Thank you for responding to my post. My envirnoment is a Exchange 2010 on Windows Server 2008 R2 (w/ Hyper-V VMs) 1. I have followed similar documents completely. Are you saying that I'll have issue inspite of the what I have configured so far? 2. In the case of Site B I have to configure CASArray as outlook2.domain.local? How does Site A to Site B or vice-versa fail-over happens? Thanks

About that Hyper-V issue, I think Jon just provided you as for reference to ensure that you won’t encounter the same issue About the CAS array failover between sites, the following resources may help: Cas Array HA 2 sites First question under the “Client Access Design” section in Exchange Queue & A: CAS Arrays - Server Roles, Client Creation, Load Balancing and MoreJames Luo TechNet Subscriber Support (http://technet.microsoft.com/en-us/subscriptions/ms788697.aspx) If you have any feedback on our support, please contact tngfb@microsoft.com

James, as I read thru' the discussion, I'm confused the Hardware load balancer is running at same site (assuming based usuage of same IP address). But I'm using WNLB. I want CASArray1 service Site A and CASArray2 service Site B. When any one of them fails it should service other site. Can this be done? Thanks

Per my knowledge, such automatic failover between sites can’t be accomplished with WNLB James Luo TechNet Subscriber Support (http://technet.microsoft.com/en-us/subscriptions/ms788697.aspx) If you have any feedback on our support, please contact tngfb@microsoft.com

I agree with JamesJonas Andersson MCTS: Microsoft Exchange Server 2010, Configuration | MCITP: EMA | MCSE/MCSA Blog: http://www.testlabs.se/blog

Thanks James and Jon. Though there is no automatic failover what changes need to be made for manual failover to happen?

Per my knowledge, you need to change the “RpcClientAccessServer” parameter manually Set-MailboxDatabaseJames Luo TechNet Subscriber Support (http://technet.microsoft.com/en-us/subscriptions/ms788697.aspx) If you have any feedback on our support, please contact tngfb@microsoft.com

Understood. Thanks James.