Microsoft Dynamics CRM is very agnostic with regards to the email platform that it works with. Whilst it will of course work very well with Exchange it is happy use any email platform through the use of a separate component called the Email Router.
Today whilst working on a demo machine with no email configured I cam across a nice warning message:
Pending e-Mail warning
This was warning me that I had created emails in CRM but that CRM had not been able to send them. No surprise as I didn’t have any email set up but it is nice to know that if there is a problem Dynamics CRM will warn you and not leave you blissfully assuming that your business critical email had been sent when it hadn’t.