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Domel_163525's avatar
Domel_163525
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Oct 27, 2015

Exchange 2010 load balanced via BIG-IP

Hello guys,

 

Currently we have our Exchange (2x CAS servers) configured via BIG-IP. The Exchange VLAN is stretched up to F5 so VS and 4x CAS servers sits within the same VLAN/Subnet which works fine.

 

I'm working on migration to a new/separate BIG-IP appliance and was wondering what is the downside/disadvantage of having exchange VS in a different VLAN/Subnet? I know there is an option to get this configured on F5 via iApp ("Same subnet for BIG-IP virtual servers and Client Access Servers" or "Different subnet for BIG-IP virtual servers and Client Access Servers") but not too sure if everything will work as works right now. The CAS servers default gateway is pointed to the VLAN interface configured on our main router (NOT VS sitting on F5) and would like to keep it that way.

 

I'm asking as I have recently been told the DNS for autodiscovery.domainname.co.uk has to be pointed to the IP address which lives in the same VLAN/subnet as the IP addresses of CASes otherwise DAG will not work...

 

Has anyone tried that?

 

I would much prefer to have only 2x VLAN configured on F5 appliances (Internal VLAN & External VLAN) rather than 3x.

 

cas
dag
devops
exchange
iapp
iApps

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  • Dayne_Miller_19's avatar
    Dayne_Miller_19
    Historic F5 Account
    Oct 28, 2015

    Hi Domel-

     

    There's no problem locating the CAS servers on the same subnet/VLAN (often called a "one-armed" topology). If you use the iApp to do your configuration, it will automatically create a "SNAT" to enable return traffic to get back to the BIG-IP without requiring routing changes on the CAS servers.

     

    Where did you hear the information about Autodiscover? It's incorrect. And DAGs don't use Autodiscover. In fact, I believe recommended configuration from Microsoft is to have a dedicated network for DAG replication, and that wouldn;t be a network to which client traffic would ever have access.