i'm running an ubuntu vps which hosts at least 2 different sites/domains via apache2's virtualhost, and they've been working fine for months. now i'm wondering about setting up some subdomains, and utilising email for the current domains i host.
i've read through posts and articles about setting up bind9, and even articles about how email actually works and it's journey from MTA to MTA( theres more to just clicking 'Send'), but my understanding is still a bit flaky here.
one of my questions is: linearly speaking, if i set up a sub-domain/sub-zone with my BIND9, assuming that it's currently installed but not running( no bind9 or named processes shown), will the bind9-DNS sever sit between my vps service provider's nameservers and my apache2-HTTP server?
example: [ns1.serviceprovider.com] > [BIND9 DNS server] > [Apache2] > [sub.mydomain.com]
and not only do i have to create records for the new sub-domain/sub-zone, but also the necessary records for all of my current domains too?
my other question is: i know email is working on my server, as i can check and send via
dig mydowmain.com MX and it shows there is a MX record pointing to my servers ip, so why do i not receive an email i sent to
the user 'postmaster' doesn't exist, but in the aliases file it shows
i appreciate any help you guys can give, and i know these questions seem a little noob, but we all started out as noobs at some point ;)