Replacing Existing CAS Array (Full Version)

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Mankney1 -> Replacing Existing CAS Array (28.Nov.2012 6:27:38 AM)

Hi, I have an existing CAS array for a 3 node DAG that we need to change. We need to replace the CAS1 array with CAS2. I think I have most of it figured out but any comments on how to do it would be appreciated. I want to make sure that the internal Outlook clients can still connect properly.

Autodiscover is working and we are using SCP.

First I would need to run this command

Get-AutodiscoverVirtualDirectory | Set-AutodiscovervirtualDirectory -InternalUrl <FQDN of our new CAS array> will change the autodiscover to the new CAS array.

I then run the Remove-ClientAccessArray command to delete the original CAS array and then run New-ClientAccessArray to create the new one.

I then create the new Internal DNS record that points to the new CAS array IP number.

What I am not sure is that since we are replacing the existing CAS1 array do we need to
Get-MailboxDatabase | Set-ClientAccessArray -RPCClientAccessServer -FQDN "FQDN of CAS Array"

I know the above command is run when you have existing DB's with no array and you are adding an array. I am not sure if it is needed if you are replacing an existing array.

Does all this seem right?

Thanks for everyone's help.

de.blackman -> RE: Replacing Existing CAS Array (28.Nov.2012 8:29:12 AM)

Is there any reason you want to change the CAS array name itself? You can always leave the same name so that there is no disconnect for your Outlook users and instead replace the servers that are members of the array.

Mankney1 -> RE: Replacing Existing CAS Array (28.Nov.2012 9:00:20 AM)

Basically we have all the internal servers that relay mail off the Exchange server pointing to the original CAS1 array.

We are putting in a Kemp HLB and we were told by our Exchange Consultant that the load balancer would break the mail relay portions if we moved the CAS1 record to the HLB. Since we have a large number of devices that use the Exchange system as a relay we figured it would be easier to leave all of them to use the old CAS1 DNS record and then have the Outlook MAPI clients use the new CAS2 array which would point to the virtual IP of the HLB.

de.blackman -> RE: Replacing Existing CAS Array (28.Nov.2012 9:16:14 AM)

I do not see how that can be possible because you can only have one client access array per AD site (check out

Also I do not see how this can break mail flow. I understand that you have your application servers pointing to the Casarray name or IP but once you have the load balancer configured properly not only for CAS traffic but also for SMTP traffic, mail flow will be fine.

Mankney1 -> RE: Replacing Existing CAS Array (28.Nov.2012 9:32:15 AM)

I am waiting for clarification on this by the consultant but I think he is out for the week.

We would only have one CAS array because the old CAS1 is deleted before we add the new one named CAS2.

The old CAS1 DNS record would still be used for SMTP relay.

Thanks for the continued input I am trying to sort all this through and this is good information.

de.blackman -> RE: Replacing Existing CAS Array (28.Nov.2012 9:39:08 AM)

What is CAS1 currently pointing to? Do you already have the CAS servers load balanced at the moment?

If thats the case, why not configure CAS1 DNS to point to one of the hub transport servers until CAS2 is configured. Then you can possibly change CAS1 to point to the same IP address as CAS2.

Mankney1 -> RE: Replacing Existing CAS Array (28.Nov.2012 10:00:28 AM)

Right now we are not load balanced. Our Exchange servers are all CAS/HUB/Transport roles. The current CAS1 points to
a secondary IP address on one of the multi-role servers. If this server would crap out we would assign the IP to the other Exchange server.

One of the issues is that many of those applications that use mail relay point to the IP of CAS1 and not the DNS because the application only allows IP.

I have posted a question on Kemp's load balancer site about load balancing SMTP. As you said why can't we load balance the SMTP. It would make it much simpler for everyone.

de.blackman -> RE: Replacing Existing CAS Array (28.Nov.2012 10:06:09 AM)

AHA ok[:D]...I see the light now

This may be a good time to change your applications to use a name an FQDN as opposed to an IP address. But I think you also see the light and are on the right track.

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