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Kevin LitmanFlag for United States of America

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Exchange 2010 NLB Connection Issue

Here is my setup.

2 CAS servers using Windows Network Load Balancing.
2 MBX/HT servers with a DAG setup.

My issue is when I want to take one of the CAS servers offline. If I go into NLB and stop the host then any client that was connected to that host will lose connectivity in outlook and owa. The lost connection can be up to a minute long, which is unacceptable. I maintain a ping of the nlb cluster ip when I stop a host.

Before anyone asks. Yes, I have my CAS Array setup with both CAS servers as members. Yes, I have my DNS A record configured correctly.
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Configure the NLB on something other than the CAS-machines.

Say you have TMG/ISA or some other appliance doing the NLB, it will then point to either CAS behind it. When a CAS goes offline the new requests will simply go to the available CAS.

If the users connect directly to the CAS that is going offline it will take time before the path to that server refresh over the network. If they however connect to TMG/ISA/Appliance it will direct the traffic behind it.
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Anybody else have any other suggestions?
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Kevin Litman
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My solution to use a hardware load balancer was a better fit for the environment.
Here's a guide for load balancing with TMG.

Using a hardware load balancer falls under "Configure the NLB on something other than the CAS-machines" as I said in my previous post. Having a ISA/TMG was only a suggestion from my part. I've recently started using Citrix Netscaler VPX for load balancing applications.