I am adding an Exchange 2010 Server to to an existing Exchange 2003 Organization and will co-exist for about a month.
My internal domain name theirdomainname.com is the same as the public or external domain name. There are a lot of PCs in multiple cities in this domain, so changing the domain name (e.g. internal.theirdomainname.com) would be very much undesirable.
Does anyone see any problems with leaving this internal domain name "as is"?
I realize that I would need to get a multi-subject cert with theirdomainname.com, mail.theirdomainname.com and autodiscover.theirdomainname.com, etc. and will need to set their internal DNS entries to point to their internal IP addresses.