Hello,
Looking for some guidance. Scenario (using fictitious DNS names):
- Two separate entities, part of a single conglomerate
- Single forest, empty root, 2 child domains DomA.org and DomB.org
- DomA was previously using Exchange 2003, which is still operational but doesn't host active mailboxes
- DomB had Exchange 2010 deployed and mailboxes + PFs were moved from DomA (E2K3) to DomB (E2K10)
- DomA external SMTP namespace was OLDDOMAIN.ORG
- NEWDOMAIN.ORG external SMTP namespace was created for Exchange 2010 deployment and it became primary SMTP address; OLDDOMAIN became secondary
- Anything addressed to NEWDOMAIN.ORG is routed via E2K10.
- OLDDOMAIN.ORG is still routed via E2K3
For various reasons, management wants to bring back the mailboxes that were previously hosted in DomA.org (OLDDOMAIN.ORG) to their original home:
- DomB will keep the existing Exchange 2010 installation with the mailboxes associated with this entity
- DomA should be upgraded to the latest version of Exchange, without disrupting DomB's operations. Exchange 2013 is desired, however, Exchange 2010 will be acceptable as well.
- Namespace NEWDOMAIN.ORG will remain with DomB
- OLDDOMAIN.ORG will be re-assigned to DomA, once Exchange infrastructure is ready
Questions are:
- Should Exchange 2003 infrastructure in DomA be fully de-commissioned and cleaned out of AD before Exchange 2013 is introduced?
- Because NEWDOMAIN.ORG has to remain available for users that are being moved back (in case anyone replies to messages sent while NEWDOMAIN.ORG was primary SMTP) - what are the caveats of CAS to CAS routing between Exchange 2010 and 2013?
- Should the load balancer be pointed at 2013 or 2010 CAS servers if NEWDOMAIN.ORG will still be routed via DomB's infrastructure?
- What would be the implications of this "divorce" for the SSL certs (all are SAN certs- e.g. expen$ive if must be re-issued)
Any other tips are greatly appreciated!
Thanks in advance.