We're in the process of attempting a migration from Exchange 2003 to Exchange 2010 over one of the next weekends. As this is my first attempt at a migration I wanted to mess up as little as possible.
I found a step -by-step walk though which I'm going to follow but wanted to know if installing the new server with a typical exchange server install along with Client access role mail.xxx.com and mail flow setting will effect my current users/server?
I'd like to get the new software installed so that I can start to look around in it but not at the expense of causing problems for my users.
You should also stop and the disable Client Access and Transport services on the new server until you can get the trusted certificates installed. that way you will prevent Outlook clients from hitting it.