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Answered Use ISA server as a load balancer for CAS / HT servers ?

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      Tuesday, March 02, 2010 9:03 PM
       
       
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      Is it possible to Use ISA server as a load balancer for CAS  and  HUB servers ?
       

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    • Wednesday, March 03, 2010 2:42 PM
       
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      As far as I know, yes. You would need to use Windows NLB or a hardware balancer capable of balancing MAPI/RPC if you want to create a CAS array.
      Brian Day, Overall Exchange & AD Geek
      MCSA 2000/2003, CCNA
      MCITP: Enterprise Messaging Administrator 2010
       
    • Wednesday, March 03, 2010 3:16 PM
       
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      Brian is correct ISA or TMG cannot load balance RPC traffic it can only load balance Internet protocol traffic )-:  ( HTTPS,OA) if you do want RPC traffic load balance you need hardware load balancer to achieve the desired goal. The KB below is not clear and caused some confusion among many people. AFAK the request for updating below KB and similar ones has been made to Exchange team.


      NLB and clustering is bit tricky, from what I have learned recently (-:

      WNLB with HT/CAS is possible but not recommended!!!!!! (Network flooding & lack of service awareness)
      WNLB MBX+CAS is not Possible = because limitation build into Windows (hard-blocked)



      http://technet.microsoft.com/en-us/library/dd979781.aspx


      best,
      ocd
      Oz Casey, Dedeal MVP (Exchange) MCITP (EMA), MCITP (SA) MCSE 2003, M+, S+, MCDST Security+, Project +, Server + Http://smtp25.blogspot.com (Blog Http://telnet25.spaces.live.com (Blog) Http://telnet25.wordpress.com (Blog)
       
    • Friday, March 05, 2010 8:07 AM
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      Hi,

      Please understand that with Exchange Server 2007, outlook connect to the mailbox directly.  If you are talking about Exchange Server 2010, then I think you can create CAS array to load balance of RPC,HTTP...

      We recommend to create CAS array on HLB(hardware load balance). If we do not have the hardware, then you can use NLB.

      After you have create the CAS array, I think you may need to publish CAS via ISA.

      ISA 2006 SP1 Configuration with Exchange 2010
      http://msexchangeteam.com/archive/2009/12/17/453625.aspx

      How to setup an Exchange 2010 CAS Array to load balance MAPI
      http://blogs.technet.com/ucedsg/archive/2009/12/06/how-to-setup-an-exchange-2010-cas-array-to-load-balance-mapi.aspx

      Regards,
      Xiu

       

    All Replies

    • Tuesday, March 02, 2010 9:45 PM
       
       
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      You can use ISA to load balance HTTP traffic on CAS servers. You'd need something else to load balance RPC if you're looking to do a CAS array.
       
    • Tuesday, March 02, 2010 9:57 PM
       
       
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      Do you have an Edge server between the internet and HUB or is it just Internet --> ISA --> Hub Transport?

      Brian Day, Overall Exchange & AD Geek
      MCSA 2000/2003, CCNA
      MCITP: Enterprise Messaging Administrator 2010
       
    • Tuesday, March 02, 2010 10:01 PM
       
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      Hi Anand,
       
       Its Possible to Configure ISA for CAS Load Balancing. Hub Server doesn't need Load balancing as it has its own built in Load balanching technology.

       Exchange Server 2010 is designed to take full advantage of the features that are available in Microsoft Internet Security and Acceleration (ISA) Server 2006.
       
       ISA Server 2006 can load balance client requests and send them to an array of Client Access servers. When ISA Server 2006 receives a request for a connection to Outlook Web App, it selects a Client Access server and then sends the name of the Client Access server back to the Web browser in a cookie.

       Ref to:
       Exchange 2010 - Using ISA Server with Outlook Web App
       http://technet.microsoft.com/en-us/library/aa996545.aspx

       All the Best :)
      Sathish Kumar Elango | MCSE 2003 & MCSA Messaging | http://msexchangehelp.wordpress.com
       
    • Tuesday, March 02, 2010 10:50 PM
       
       
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      It is just Hub --> ISA --> internet.
      So Yes I will need to load balance mapi traffic as well as smtp. Can ISA do that ?
       
    • Wednesday, March 03, 2010 10:33 AM
       
       
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      Am  I correct to say that ISA can only load balance web traffic ?
       
    • Wednesday, March 03, 2010 2:42 PM
       
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      As far as I know, yes. You would need to use Windows NLB or a hardware balancer capable of balancing MAPI/RPC if you want to create a CAS array.
      Brian Day, Overall Exchange & AD Geek
      MCSA 2000/2003, CCNA
      MCITP: Enterprise Messaging Administrator 2010
       
    • Wednesday, March 03, 2010 3:16 PM
       
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      Brian is correct ISA or TMG cannot load balance RPC traffic it can only load balance Internet protocol traffic )-:  ( HTTPS,OA) if you do want RPC traffic load balance you need hardware load balancer to achieve the desired goal. The KB below is not clear and caused some confusion among many people. AFAK the request for updating below KB and similar ones has been made to Exchange team.


      NLB and clustering is bit tricky, from what I have learned recently (-:

      WNLB with HT/CAS is possible but not recommended!!!!!! (Network flooding & lack of service awareness)
      WNLB MBX+CAS is not Possible = because limitation build into Windows (hard-blocked)



      http://technet.microsoft.com/en-us/library/dd979781.aspx


      best,
      ocd
      Oz Casey, Dedeal MVP (Exchange) MCITP (EMA), MCITP (SA) MCSE 2003, M+, S+, MCDST Security+, Project +, Server + Http://smtp25.blogspot.com (Blog Http://telnet25.spaces.live.com (Blog) Http://telnet25.wordpress.com (Blog)
       
    • Wednesday, March 03, 2010 4:17 PM
       
       
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      If i go with a hardware load balancer solution, Do I need to purchase 2 hardware load balancers so there is no single point of failure ?

       
    • Wednesday, March 03, 2010 4:37 PM
       
       
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      That would be up to you and your organization to decide, but generally yes if there is only a single device it is a potential failure point. The various HW vendors can help you with that decision.
      Brian Day, Overall Exchange & AD Geek
      MCSA 2000/2003, CCNA
      MCITP: Enterprise Messaging Administrator 2010
       
    • Wednesday, March 03, 2010 9:13 PM
       
       
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      Can I use windows NLB for my CAS/HT servers ? I want to load balance rpc, web, as well as smtp
      Possible ?

       
    • Friday, March 05, 2010 8:07 AM
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      Hi,

      Please understand that with Exchange Server 2007, outlook connect to the mailbox directly.  If you are talking about Exchange Server 2010, then I think you can create CAS array to load balance of RPC,HTTP...

      We recommend to create CAS array on HLB(hardware load balance). If we do not have the hardware, then you can use NLB.

      After you have create the CAS array, I think you may need to publish CAS via ISA.

      ISA 2006 SP1 Configuration with Exchange 2010
      http://msexchangeteam.com/archive/2009/12/17/453625.aspx

      How to setup an Exchange 2010 CAS Array to load balance MAPI
      http://blogs.technet.com/ucedsg/archive/2009/12/06/how-to-setup-an-exchange-2010-cas-array-to-load-balance-mapi.aspx

      Regards,
      Xiu