one of our Client has only one Server with OS 2008 Standard, run as Domain Controller & Exchange Server 2007. There are 200 Mailboxes user over internet. domain is also Public on internet.
They Bought 2 New servers and Need to Migrate and Upgrade both Domain & Exchange; How to Achieve these Goals with best Practice
1- Domain Migration to Server 2012 R2 with DNS server. Need to Put IP Address of Old DC to New one as they have only one Public IP Address.
2- Exchange 2007 Server Installed in Same Server with All roles, it Internet Facing and Need to Migrate/Upgrade to another Server with exchange Server 2013.
What are the precautions should be Taken to overcome any issues, as Its Running Environment and Cannot make long down time.