Sendmail to Relay different domains to different hosts

[Giorgos Keramidas]

On Fri, 6 Feb 2009 13:15:02 -0500, <Greg.Stark at sungard.com> wrote:
> I am using Sendmail on a FreeBSD7.0 server as a mail relay for some of
> our servers.  These servers relay messages to both internal recipients
> and external customers.  I need to be able to relay mail destined to
> our internal domain recipients to our corporate mail servers but relay
> everything else out to our usual smart host.  So basically, I am
> looking to relay emails destined for a certain domain to one host and
> the rest of the mail to another.  Does anyone know how I could
> configure sendmail to accomplish this?

That's what `mailertable' is for.

Enable in your `sendmail.mc' file the mailertable feature:

    FEATURE(`mailertable', `hash /etc/mail/mailertable')

Then create an `/etc/mail/mailertable' map with something like:

    @internal.domain            esmtp:[internal.relay.host]

Generate the `mailertable.db' map with makemap:

    # cd /etc/mail
    # makemap hash mailertable < mailertable

and you're done.