DAG and CAS Array in 2 different subnets

Posted on 2010-11-18
Last Modified: 2012-05-10
I have 4 Exchange Servers. 2 MBX/HT & 2 CAS (Windows 2008 Ent / Exch 2010)

DAG is working fine and i have also configured CAS array (not tested yet)

They are all in same subnet. I need to take 1 MBX/HT server and 1 CAS array to DR site that has a different subnet. My question is, Would my DAG continue working as it is now? Im hoping to remove 1 member of my CAS array and re-add with new IP in different subnet. Would this work?

IP Addresses for my servers are below

EX2: (CAS)

EX4: (CAS)

CAS Array:

My new IP for
EX4: (CAS)

I have not installed critical updates from Exch2010 CD due to some proxy issues. I can install normal windows updates but exchange updates (from CD) are not going through for some reasons.

Question by:MANGO247
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LVL 49

Accepted Solution

Akhater earned 500 total points
ID: 34162921
1. CAS arrays are per site so if you move your CAS server to another site you will need to have another CAS array
2. for your DAG you will need to add an additional IP for the DAG from the other range also so you DAG will have 2 IPS and

Author Comment

ID: 34162986
Could you explain the steps for having an additional IP in DAG?

What if i want to use 1 CAS server instead of Array on each site? Do i simply break CAS array and move the server to DR? I want to know what are further steps to make sure that i have a fully functional exchange server at DR site so if i lose my main site users cant still connect to exchange at DR.

LVL 49

Expert Comment

ID: 34163200
for the DAG go to org config, mailbox, dag right click properties on your dag name. In the second tab you can add the ip there (assuming you have sp1 installed)

for the cas array yes you can delete your cas array and have one single cas server in each site
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Author Comment

ID: 34163746
For CAS Array, can we stretch our vlan across 2 sites and then have cas array with a server in each site and same for DAG. With out needing to add an additional ip from a different subnet we can simply move 1 member of DAG to DR and connect to same VLAN?

Would you agree with this design? We dont have many Exchange users so traffic will always be down but this will give us full resiliency?
LVL 49

Expert Comment

ID: 34165449
you could however I don't see the need to do this

Author Comment

ID: 34180434

Author Closing Comment

ID: 34180436

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