Configure sendmail to reject mail for unknown users?

[Timothy Alberts]

On Tue, 2006-03-14 at 02:26 +0000,
replies-lists-redhat at listmail.innovate.net wrote:
> are you sure there isn't an MX-record/host for the domain in question?
> if it's "msiscales.com" there are two - so in that case, by the time
> the mail reaches your internal mail server it's too late (you're
> dealing with post-acceptance bounces, not bounces on delivery).

Yes, it is 'msiscales.com'. The second MX record is supposed to be a
backup when our server is down.  The mail should be coming to us first,
I think that's reflected by the priority within the DNS MX record.
Which as you say, when our server goes down, all mail goes through our
backup and we get bombarded with the spam and there's nothing I can do
but try and filter it.  Under normal circumstances, all mail should come
to the main server in question where I want it to be rejected.