virtual hosting checklist?
 

what ive got so far:

a registered domain w/ server & services, .. this is also my gateway server

i need to set up more servers behind the gateway server, to relocate services to be behind the gateway

im assuming that db.mydomain.outside is where i add the name of the "webmail" host,
and that i add that host by giving db.mydomain.outside the local IP address & name of the webmail server

i may be incorrect in my assumption, if i am please correct me.
i must be incorrect because it doesnt work..
if i query my nameserver about "webmail" .. no such blah .. "webmail.mydomain.com" ..no such blah .. of course "mydomain.com" does in fact work ..

can someone please fill me in on what im missing?

i appreciate the help