We have a qmail server sitting on a dmz behind a firewall. We wish this
to be the main smtp server and have all incoming mail sent to it. So say
we are domain.com, then our MX record for domain.com points to
mail.domain.com. This works fine.
Recently one of our divisions decided it wanted to use it's own (exchange)
server. They want to be able to receive mail for <user>@sub.domain.com.
This machine (sub.domain.com) is behind the firewall. I would like for
our main mail server, mail.domain.com to recieve all messages for
*.domain.com and relay it to wherever it needs to go. I believe the
terminology is mail hub.
Anyway, the smtproutes file on mail.domain.com reads:
sub.domain.com:[10.2.11.12]
Sending email to [EMAIL PROTECTED] from anywhere internally works fine.
It gets to mail.domain.com and is then routed to sub. However, when
sending email to [EMAIL PROTECTED] from the outside, messages bounce
back with the error "sub.domain.com: host not found" or similiar. My
understanding about email routing is that the MTA is supposed to look up
the MX record for domain.com and send the message there.
Or is it that I need to have an MX record for sub.domain.com? Either way
I sub.domain.com does not resolve to anything currently.
I guess my question is if I need to do something to the DNS server or is
there a way to avoid this?
