[BlueOnyx:19711] prevent user from sending e-mail in /etc/mail/access

[Meaulnes Legler]

dear list

with iptables, I have been able to stop the e-mail flooding attacking a 
specific user, see previous post [BlueOnyx:19698] Re: e-mail flooding

But that user is still sending out tons of mails if I enable it again 
(unchecking «Suspend» in the GUI), thousands in a couple of hours with 
subjects like:
	Subject: Warning: could not send message for past 4 hours
	Subject: Returned mail: see transcript for details
That user must have some virus and I'm afraid that my server will be 
tagged...

I read that I could prevent user from sending e-mail by adding these 
lines to /etc/mail/access
	From:janis at legler.org	REJECT	# Reject user from sending mails
and restarting sendmail. But /etc/mail/access is pretty much empty:

--------------------------------------------
# By default we allow relaying from localhost...
Connect:localhost.localdomain           RELAY
Connect:localhost                       RELAY
Connect:127.0.0.1                       RELAY
# Cobalt Access Section Begin

# Cobalt Access Section End
/etc/mail/access lines 1-15/15 (END)
--------------------------------------------

Can I do so as said above without compromising the mailer?

Thank you and best regards

Meaulnes Legler
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~ http://www.WaveWeb.ch ~
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~  Zurich, Switzerland  ~
~  +41\0 44 260 16 60   ~
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~