I am in the process of upgrading to Exchange 2013 from Exchange 2007. I plan on coexisting with the current Exchange 2007 server until I get all of the mailboxes moved.
Our current mail server's hostname is mail1.domain.com with the internal and external DNS of mail1.domain.com. I plan on changing the Exchange 2007 server service urls to legacy.domain.com and creating internal/external DNS records that point to the correct
location. The problem that I am running into is what to set the internal urls for the Exchange 2013 server (mail2.domain.com). I cannot use mail1.domain.com internally since the hostname of the Exchange 2007 server is mail1.domain.com. If I set the Exchange
2013 internal service urls to mail2.domain.com and then set the external urls to mail1.domain.com, will that cause any issues when I do the external DNS swap? Will this cause any impact on cell phones that are tied to our Exchange 2007 server?