Problem with WNLB with virtualised CAS Servers

Dear Experts,

I have following environment:

2 x CAS EXchange 2010 Servers
2 x MB Exchange 2010 Servers

MB Servers are configured with DAG and working fine, now i am trying to configure  WNLB on CAS Servers, The operating System i have is Windows Server 2008 R2 SP1, All Servers are in same VLAN.

Issue:
I created NLB Cluster on CAS01 and all went ok, as soon as i added CAS02 in that cluster. CAS01 cannot ping to MB 02 and CAS02 cannot ping to MB 01 and vice versa.

whereas cas 01 can communicate with MB01 and CAS 02 can communicate with MB02.

Please advise asap. i am stuck with this strange issue.
MCIT-LibyaAsked:
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MASEE Solution Guide - Technical Dept HeadCommented:
Hi,
FYI WNLB is not longer supported by MS Exchange team.
I strongly recommend to buy a cheap load balancer of your budget to make your systems supported by MS.
If you want to go ahead with WNLB you can reconfigure as in this article.
http://exchangeserverpro.com/how-to-install-an-exchange-server-2010-client-access-server-array/

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Peter HutchisonSenior Network Systems SpecialistCommented:
In the WNLB console, you need to fine tune the ports to determine which ports should be load balanced and which ports are server specific. See Port Rules.
Load balanced ports: 80, 443, 25, 110, 143 etc
Server ports: ICMP for pings, File and Print sharing (SMB) etc

https://technet.microsoft.com/en-us/library/bb633031.aspx
AkhaterSolutions ArchitectCommented:
Yous issue is due the the Hyper-Visor, you have to enable Enable MAC Address Spoofing  on the NICs from inside hyperV for that to work as shown in this picture

https://msdnshared.blob.core.windows.net/media/TNBlogsFS/prod.evol.blogs.technet.com/telligent.evolution.components.attachments/13/7308/00/00/03/27/24/60/MAC%20address%20spoofing.png
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Windows Server 2008

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