There used to be a hack/tweak for this years ago. It's found on the wayback machine here:
https://web.archive.org/web/20110729131804/http:/www.sant-media.co.uk:80/2010/03/how-to-configure-exim-to-receive-email-for-domain-only-from-specific-ip-addresses#more-360
The last time I tried that, I believe it broke things badly.
We still are looking for the right code to use in Exim to limit incoming mail to
1) the domains we serve -- have that
2) authenticated SMTP users who use Outlook or whatever
3) just ONE other IP address, the spam filter for our network
Ideally, drive by spammers and anyone attempting to send mail TO our users would be blocked completely from accessing the SMTP server with a message like, "This server does not accept mail directly. Use the MX server."
Can anyone offer some advice on what to use in the current version of Exim? The solution above used to work, but in the iteration of versions, it seems to have been outdated somehow. If we're simply putting things in the wrong place now, finding the right location would be appreciated.
--
Craig Thompson, President
Caldwell Global Communications, Inc.
