how to setup a domain on the a domain registrar -with out waiting for Dns Updates.
purchase domain at a domain registrar like cheap domains or godaddy
locate your ip address for your webserver in your welcome email
login to registrar add ips or edit host records
change ip address to your above ip for the following
-*
-www
-@
create a record for mail
create a txt record for spf entry
v=spf1 ip4:x.x.x.x/32 ~all"
creat mx record...