Hellow friends,

i m new boy in linux, i wan't to make new mailserver on my localmachine . My OS is Cent OS , i wan'ts to use Mailserver of My Hosted Server for junk avoid, which ever is working fine. my hosted Server & localmachine between a firewall machine.
my ques. is how to use mail server on my localmachine in case use hosted mailserver ? what are DNS Records, Port forwording, mailserver setup on localmachine & how to use it..

please....

Thanks in advances...