Mail Attack

[Jessica Zhu]

Hi,

It looks like we are experiencing the mail attack now.

In our maillog, we have a lot of User Unknown message like the following.

Aug 23 11:52:25  s1 sendmail[2110]: j7NFqPL02110:  
<Oscard at mathforum.org>... User unknown
Aug 23 11:52:25 s1 sendmail[2110]: j7NFqPL02110: from=<>, 
size=17601, class=0, nrcpts=0, proto=ESMTP, daemon=MTA,  
relay=mail.vis-inc.net [66.77.28.202]

It looks like that all the from is <>, does anyone have the way to fight 
against it. 

Jessica