Relay and spam

[Bluecrack]

I have a sendmail server running our our DMZ that relays for my domain. It forwards mail to an internal server running Lotus Notes. Well, Lotus Notes is apparently configured very strangely. I don't manage it so I can't fix the problem that way (the right way). Basically Notes looks at an email address and drops everything to the right of @ symbol and the @ symbol. Then it looks through 4 or so fields in it's directory to find the best match for an email. One of the fields is the firstname. Again, I don't know why it's setup like this. It's managed by our parent company.

Here's the problem, email addressed to <firstname>@domain.com gets routed to somebody it should not. So I'm looking for a solution that will allow me to block all email to my domain except those addresses I specifically permit.

As far as I can tell sendmail does just the opposite. I provides a facility that allows the server to accept all email except for those addresses specifically denied in the access.db. Is there a way to deny all email to <domain.com> by default and then allow through those specific email addresses I want?

Any help would be greatly appreciated.
Bluecrack

P.S. - The server runs MailScanner with spamassassin so if there is a better way to do it with those guys, I'm open to trying.

 

[Orenf]

are you essentially looking to block directory harvest attacks - to only allow mail for validated users to reach your domain?
if so, you might want to consider a perimeter filtering service, such as the one provided by Electric Mail, which will filter incoming mail outside of your network, and will only deliver those addresses which you explicitly allow.




Oren Friedman