Sendmail reject non-extant hosts? RFC1123

[Kevin Kinsey, DaleCo, S.P.]

I'm not happy that Sendmail is
allowing connections from non-
existent hosts (i.e., spammers...)

I run Sendmail more or less straight
"out of the box" on -stable.  I had
been under the impression that the
line

ALL : PARANOID : RFC931 20 : deny

in /etc/hosts.allow would help reject
some of this stuff.  However, as the
amount of spam in my inbox is
beginning to attest, this isn't the case.

I've been googling and searching the 
archives with strings similar to the
one in the title, and haven't yet grok
what I'm supposed to do to get this
to work...

So, how do I tell Sendmail that if
a host doesn't exist, (i.e. d3kr890d.129ddk.org)
I don't want to talk to it...

Kevin Kinsey