No Subject

[R_Yeo]

Hi,
 At work, we have a Class C address with it's own mail server. 
My Linux box is configured with sendmail to reply to mail addressed to
me via my ISP.  Corporate IT is clamping down on smtp servers due to 
spammers.  Is there anyway to close down my smtp port (25) so that it
will not be listening or only listening to the local host?  I
only want to use it to send.  Corporate IT does a periodic scan of
the port to look out for unauthorised servers.
 OTOH, if someone has a suggestion for qmail or postfix, I'm all
ears.
--
Ronald