Configure sendmail to reject mail for unknown users?

[Steven W. Orr]

On Monday, Mar 13th 2006 at 14:56 -0800, quoth Timothy Alberts:

=>I should ask a sendmail list, but this is the most responsive,
=>knowledgable group I've ever dealt with so...
=>
=>How can I configure sendmail to reject mail for users that don't exist?
=>One of the annoying things that happens to my FC4 mail server all the
=>time is spammers/viruses will use fake accounts such as
=>'fakeadmin at mydomain.com' and my server always takes it because the
=>domain is correct.  It just gets delivered to the
=>postmaster at mydomain.com , I'd rather it not get into my server at all.
=>
=>I think there are milters for sendmail to check against LDAP, but I
=>don't know the details of it yet, and I don't have an LDAP setup for the
=>my domain yet (still learning).  I was wondering if there is a way just
=>to configure sendmail to reject mail if it has a To: CC: or BCC: of a
=>user that doesn't really exist for a domain.

You have to go out of your way to accept mail for no-existant addresses. 
Here's what I used to do:

define(`LUSER_RELAY', `local:postmaster')

inside my sendmail.mc

If you comment that out then mail going to non-existant users will be 
rejected.

-- 
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steveo at syslang.net