Setup Exchange 2010 CAS Array to load balance MAPI

This entry was posted by on Friday, 23 April, 2010 at

Since Exchange 2010 CAS servers now handle all internal and external client traffic to Exchange mailbox servers including Outlook MAPI traffic, the need for a highly available CAS array is critical to your design. So how do you load balance MAPI traffic:

Image Cas Array Exchange 2010

1. First you must have a Loadbalancer for your CAS Servers or you must enable Network Load Balance.
2. Create a MAPI A record in your internal DNS infrastructure that resolves to the Virtual IP Address (VIP) of the CAS load balancing array. The DNS entry, for example, could be mapi.contoso.local. This a record is for internal use.
3. Configure your load balancing array to load balance the MAPI RPC ports:
   1.TCP 135
   2.UDP/TCP 6005-65535; or set static ports
4. Create in Exchange 2010 a new Cas Array with the following PS Commando:
–> New-ClientAccessArray –Name “A Friendly Cas Array Name” –Fqdn “mapi.contoso.local” -Site “Your Active Directory Site Name for this Array”

5. Configure your Database to connect to the CAS Array and not a CAS Server with the follwing Command:
-> Set-MailboxDatabase “Database Name” -RpcClientAccessServer “Your Friendly Cas Array Name”

6. Configure all mailbox databases to connect to the CAS Array with the follwing commando :
->get-MailboxDatabase | Set-MailboxDatabase -RpcClientAccessServer mapi.contoso.local

7.  Check the settings with the follwing command:
-> get-MailboxDatabase | fl -RpcClientAccessServer


Exchange 2010 Hardware Loadbalance Configuration
Cas Array Hardware Loadbalance

More Info on Microsoft Technet Site

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