Linux and Windows email server implementation

Need help in understanding these types of principles for setting up Linux and Exchange email server:
  1) ISP throttling, feedback loop, etc.
  2) SMTP protocol and email delivery systems such as Message Transfer Agent (MTA).
  3) Automating daily administration and user tasks.

I hear that SME Linux is ideal for supporting MS Windows clients and Linux clients as well.
Is that true?

Thanks!