* Marco d'Itri: > On Sep 20, Josselin Mouette <joss@debian.org> wrote: > >> If a spam is issued by an infected machine with a dynamic IP, it can use >> the SMTP server from the ISP as well. How do you make the difference >> betwen the two? > Some already do. The idea is that reputable ISPs rate-limit mail sent by > customers with cheap accounts. And there's a general rate limit imposed by the maximum throughput of the mail server. 8-)