My CTO would like our Exchange environment to have an OWA URL that would direct the user to the correct Exchange server, so: Users logs into https://webmail.domain.com/owa => Page displays Go to Exchange 1 or Exchange 2. I have the two Exchange servers setup and working, but I think I'm missing something. My suspicion is that I need a 3rd CAS server that is simply used to point the users to the correct server. Does this sound right?

1 Answer 1


Are you planning on staying with Exchange 2010 for a long time?

Exchange as a CAS can proxy the OWA connections. With a front-end server, you can have it display the content of whichever backend server the mailbox is on, without redirecting the user to a different server.


Do you have a "ExternalURL" property on the relevant virtual directory?

  • This is a development environment we use to simulate our customers Exchange environment, and until they make any notion of going to a new version of Exchange or O365, we will be sticking with 2010. So I believe what you are saying is what I was already suspecting, CAS frontend server that will display the proper OWA URL once the user logs in. Yes, I specified webmail.domain.com/owa as the External URL, but only on the two Exchange servers that I have. I believe the expectation is to see the page that tells you which OWA URL your mailbox resides on and less of an auto redirect. Dec 28, 2016 at 16:27
  • A front-end CAS will get this done for you. If this is simulating a client environment, does the client currently experience the redirection you are seeing in your dev environment?
    – E.F.
    Dec 28, 2016 at 16:32
  • Yes, when our customer logs into their webmail.domain.com the end user sees "go to this url for best performance" then they log into that server. We didn't think we would need this in depth of a setup, so we are just now putting it in place. So I will need a front end CAS server with OWA enabled, when the user logs in they will see a page displaying the OWA address for one of my two Exchange servers. Sound correct? Dec 28, 2016 at 16:35
  • With the frontend CAS, the user will see only the name of the server they logged into. They will not see "a page displaying the OWA address for one of my two Exchange servers".
    – E.F.
    Dec 28, 2016 at 16:49
  • Example: FrontEndCAS, Exchange1, Exchange1 FrontEndCAS has a DNS record and SSL cert of webmail.domain.com Users with mailbox on Exchange1 goes to webmail.domain/com/owa, they will get their mailbox, and see only the address webmail.domain/com/owa
    – E.F.
    Dec 28, 2016 at 16:52

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