[CentOS] Sendmail forwarding external email sent to root

Hello:

On a CentOS5 machine I set up for a client, in /etc/aliases, 
I set root's mail to forward to my email address so I can
get notices from cron, etc.

Unfortunately, I am now getting a lot of spam which is
sent to root at theservername.com

How can I tell sendmail to not accept external email to
root?  

I searched the Internet and found some horribly convoluted
solutions.  There has to be a simple way to do this, like
putting a line in sendmail.mc or something.

Anyone know a good solution?

Thanks
	Neil

--
Neil Aggarwal, (832)245-7314, www.JAMMConsulting.com
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