Installing CAS role for the existing Mailbox server ?

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I had this question after viewing Mailbox in CAS Server Exchange 2013.

Hi All,

Just like in the above thread, this time I want to do the other way around, What's the suggested steps for me to install CAS role on the existing Exchange Server 2013 Standard SP1 mailbox server role without losing any of its data or impacting email flow ?

Can someone please share the steps ?

I'd like to decommission one CAS server in my AD site located in the branch office:

So can anyone here please share the steps to add CAS role to the newly build production mailbox server?

AD Site: Default-First-Site name
Old Server to be decom: Mailbox & CAS role only running as OWA and ECP so far.
Windows Server 2008 R2 Std SP1
Exchange Server 2013 Standard SP1 + CU 3
PRODMBX14-VM
C:\ - OS - 200 GB
D:\ - Mailbox DB - 1989 GB

The new server: Mailbox role only in production for 1200 users.
Windows Server 2012 R2 Std
Exchange Server 2013 Standard SP1
PRODMBX20-VM
C:\ - OS - 120 GB
D:\ - PRODMBX20-VM-DB01 - 700 GB DB01 and its Tx Logs
E:\ - PRODMBX20-VM-DB02 - 700 GB DB02 and its Tx Logs
F:\ - PRODMBX20-VM-DB03 - 700 GB DB03 and its Tx Logs
G:\ - PRODMBX20-VM-DB04 - 700 GB DB04 and its Tx Logs
H:\ - PRODMBX20-VM-DB05 - 700 GB DB05 and its Tx Logs

AD Site: Head_Office
The new server to be configured as DAG with the above [This server is different AD sites & location from the two above]:
Windows Server 2012 R2 Std
Exchange Server 2013 Standard SP1
PRODMBX30-VM
C:\ - OS - 120 GB
D:\ - PRODMBX30-VM-DB01 - 700 GB DB01 and its Tx Logs
E:\ - PRODMBX30-VM-DB02 - 700 GB DB02 and its Tx Logs
F:\ - PRODMBX30-VM-DB03 - 700 GB DB03 and its Tx Logs
G:\ - PRODMBX30-VM-DB04 - 700 GB DB04 and its Tx Logs
H:\ - PRODMBX30-VM-DB05 - 700 GB DB05 and its Tx Logs

Thanks,
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Adam BrownSenior Systems Admin
Top Expert 2010
Commented:
You should be able to add the CAS role by running the Exchange installation again and selecting the option to install CAS, or (possibly, haven't tried this) opening the Control Panel, Programs and Features, and selecting the Exchange installation and clicking Change to open the installer that way (I don't have a 2013 server to try this on at the moment, so I'm not sure if this works...Just a possibility)

Author

Commented:
Yes, that what I've thought so.
I assume there is no need to reboot the whole server and Extend the AD schema?

Is there any steps that I need to be aware when adding this CAS role to my running Mailbox server that you know of ?
Adam BrownSenior Systems Admin
Top Expert 2010
Commented:
Server reboot will be necessary, I believe, but Schema changes should be taken care of already.

You'll want to make sure you set the Virtual Directory URLs and Autodiscover Service URI on the CAS role immediately after installation completes (this prevents users from receiving Certificate errors in outlook after the new CAS is online), and plan for downtime if this is a production server. Also make sure you're covered from a Disaster Recovery standpoint. Take a backup before you do anything, and make sure you have a spam filter appliance/cloud service that does mail queuing to keep from losing email during install, since the mailboxes will be taken offline at the start.
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Author

Commented:
Hi Adam,

Cool, so in this case, I will need to set the new MBX-CAS server PRODMBX20-VM with the information that I get from the below Powershell script executed on the old/existing server PRODMBX14-VM

Get-ActiveSyncVirtualDirectory | fl internalurl,externalurl 
Get-AutoDiscoverVirtualDirectory | fl internalurl,externalurl 
Get-ECPVirtualDirectory | fl internalurl,externalurl 
Get-OabVirtualDirectory | fl internalurl,externalurl 
Get-WebServicesVirtualDirectory | fl internalurl,externalurl

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The result is a bit strange since all of them pointing to OWA.domain.com and the Autodiscover are all blank ?

InternalUrl : https://owa.domain.com/Microsoft-Server-ActiveSync
ExternalUrl : https://owa.domain.com/Microsoft-Server-ActiveSync

InternalUrl : https://owa.domain.com/Microsoft-Server-ActiveSync
ExternalUrl : https://owa.domain.com/Microsoft-Server-ActiveSync

InternalUrl : 
ExternalUrl : 

InternalUrl : 
ExternalUrl : 

InternalUrl : https://owa.domain.com/ecp
ExternalUrl : https://owa.domain.com/ecp

InternalUrl : https://owa.domain.com/ecp
ExternalUrl : https://owa.domain.com/ecp

InternalUrl : https://owa.domain.com/OAB
ExternalUrl : https://owa.domain.com/OAB

InternalUrl : https://owa.domain.com/OAB
ExternalUrl : https://owa.domain.com/OAB

Open in new window


is that correct?
Senior Systems Admin
Top Expert 2010
Commented:
Correct. There are no URLs assigned to Autodiscover in Exchange. Instead, there's a CAS setting on the server itself that defines the Active Directory SCP for Autodiscover (This is what Domain joined computers will use when doing an Autodiscover lookup). You would set this by running
get-clientaccessserver | set-clientaccessserver -autodiscoverserviceinternaluri "https://autodiscover.domain.com/autodiscover/autodiscover.xml"

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Just make sure the value you set in the InternalURI matches the Certificate you're using for the servers. The CAS servers *should* be load balanced eventually, but it isn't necessary to do so immediately.

Author

Commented:
Great, many thanks Adam,

Therefore in addition to the steps above that you mentioned, I will execute the below script from the new server:

get-clientaccessserver | set-clientaccessserver -autodiscoverserviceinternaluri "https://autodiscover.domain.com/autodiscover/autodiscover.xml"

to match the SSL certificate I imported to the server :-)

is that correct or not necessary ?
Adam BrownSenior Systems Admin
Top Expert 2010

Commented:
That is correct.

Author

Commented:
Thanks Adam !

Author

Commented:
Hi,
After enabling or installing the CAS role, do I need to manually create the Receive Connectors to be the same like the existing MBX-CAS server role ?
Adam BrownSenior Systems Admin
Top Expert 2010

Commented:
There should be some default connectors created with the installation. If you haven't created any additional connectors or modified the connectors to adjust the way they function on the other servers, you shouldn't need to do anything with them.

Author

Commented:
Great, that does make sense.

hopefully tomorrow or over the weekend, I can do the CAS role installation over the existing mailbox server.

I was confused and bit worries after reading this article: https://oddytee.wordpress.com/2015/04/27/think-twice-before-installing-only-the-cas-role-for-exchange-2013/

Author

Commented:
Do I need to create the below A record in internal & public DNS as well:

A Record
Autodiscover .domain.com --> IP address of new PRODMBX20-VM
OWA.domain.com --> IP address of new PRODMBX20-VM

there is about three CAS server, but not sure why I can only find one A record which still points to the old PRODMBX14-VM server.

I assume the DNS will be round robin by itself for the CAS traffic to those IP address ?

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