>I have a problem where we suffer from emails being rejected due to reverse
>DNS lookups. I'm guessing (and I hope someone can confirm this) I need to
>move the smtp server to the DMZ, make available an external IP for this
>server, and change the servername from domain.local to something like
>smtp.domain.com.

>Now if I change the domain on the server to domain.com - all emails sent out
>via that server that need to go to user@domain.com won't actually get sent
>out. They end up residing locally.
>My question is how do I get the emails sent to users@domain.com to go out
>when the servername is called domain.com.

"Sanford Whiteman" wrote:

> >I have a problem where we suffer from emails being rejected due to reverse
> >DNS lookups. I'm guessing (and I hope someone can confirm this) I need to
> >move the smtp server to the DMZ, make available an external IP for this
> >server, and change the servername from domain.local to something like
> >smtp.domain.com.
>
> I feel like I'm writing on this a lot lately. :)
>
> You do not need to change the Windows name of this machine. However,
> you do need to create a public IP dedicated to this machine; that may
> mean putting the machine in a non-NATted DMZ, or adding a static NAT
> for it, depending on your firewall. The PTR for that IP address
> _must_ complete an EHLO-PTR-A-IP "DNS roundtrip" to ensure delivery.
> That is, the PTR for that IP must match the EHLO sent by that IP, and
> the PTR must also have a corresponding A record that points back to
> the originating IP.
>
> IIS SMTP uses the FQDN setting under Delivery-Advanced as the EHLO for
> the virtual server. By default, this is set to the Windows name of
> the machine. Changing it overrides the relationship to the Windows
> name, so you don't need to change anything outside of IIS.
>
> >Now if I change the domain on the server to domain.com - all emails sent out
> >via that server that need to go to user@domain.com won't actually get sent
> >out. They end up residing locally.
> >My question is how do I get the emails sent to users@domain.com to go out
> >when the servername is called domain.com.
>
> The VS FQDN should certainly _not_ be domain.com. The PTR record,
> which should be the same as the VS FQDN -- as I mention above, reused
> by IIS as the EHLO -- should be the canonical name assigned to the
> machine. The canonical name of the machine may be thought of as the
> "actual" or "real" unique hostname of the machine and must be a
> fully-qualified hostname resolvable using public DNS. It should
> therefore be something along the lines of smtp.domain.com. The
> virtual server's local drop directory would thus only grab messages to
> user@smtp.domain.com.
>
> Also look at recent n/g posts from me on this exact topic.
>
> --Sandy