1) please sign you messages
2) first understand the mail and dns protocols/terminology (it should
take no more than an hour, if you can find a good source) and *then*
run a server.
Apart from that I must admit your attitude is better than most, you
ask, acknowledge the replies and are prepared to listen.
I am very sorry, I just got off bed (well, not "just") on the wrong
foot (but you should see the reply the Microsoft France spammer got
from me this morning...)