Please let me know if this is correct and fill in where ever necessary. I am setting up a fresh Exchange 2003 test environment.
According to me for a working production Exchange environment (which involves inbound and outbound mails to internet), the below is true (but I am not 100% sure).
A domain name should be registered with a name registrar and mx should be published - this is to let mails from outside our network know where the mails should be sent.
Our gateway or exchange smart host will be receiving mails sent from internet and pass it to internally - i believe we define recipient policies to define what domains we receive messages for.
Do we require a connector to receive mails from internet in Exchange 2003? If no, why do we require something like a Receive connector in Exchange 2007?
I am little confused about these things. Any suggestions would be of great help.