Exchange 2010 to 2013 Migration with same DNS Names and IPs

Hi there,

following migration scenario:

1x E2010 Multirole DAG Member
1x E2010 Multirole DAG Member
no Public Folders, Outlook 2010 / 2013
fully configured internal external access

What about this:
remove dag
remove 1st E2010 srv
Install 1st E2013
Test Connectivity and Mailflow
Move Mailboxes to E2013
Remove 2nd E2010 srv
Install 2nd E2013
Build-up DAG again


No need for config on Loadbalancer, External Firewalls etc. Or am I missing something?
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Simon Butler (Sembee)ConsultantCommented:
The only way this will work is in a big bang approach - so no access to CAS during the migration period. If that isn't possible then you will need to have two IP addresses with a legacy host name in use.

Retaining the same host name etc is actually the preferred method, as it allows Exchange to control whether the CAS client is proxy or redirected.

You will still need a load balancer of some description, as you can only have the CAS DNS pointing to one or other of the servers. DNS does not provide failover.


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Marcel_DAuthor Commented:
@Simon.... Why that?

1 Server Exchange 2010
1 Server Exchange 2013

in my eyes the smallest co-existence. Why should this disrupt CAS?
Simon Butler (Sembee)ConsultantCommented:
That is why I said about the coexistence. As you haven't provided any indication of the numbers involved, it is hard to say if it is a good plan or not.
50 users, you could probably move them quickly with OWA access blocked. 500 users, not so much.

OWA doesn't proxy, it redirects, so both servers have to be seen from the internet to work correctly.

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