Many windows based SMTP servers have problems handling with "mail from: 4k_junk" 
or just "4k_of_junk". Servers that tested vulnerable include Lotus Domino 
ESMTP Services running Version 5.0.3, the CMail Server version 2.4.6, 
and the Argosoft Mail Server version 1.2.1.0. Perl demonstration code included. 
By Smiler