ISPs loved this idea. Today, most ISPs already ready block port 25. AT&T, Comcast and Verizon to name only three already do this. In practice what this means is that unless you have a static Internet Protocol (IP) address chances are you must use your ISP's official e-mail server to send mail out.
Richi Jennings, an independent e-mail analyst and writer, adds, “ISPs should do so much more, for example:
Co-operating with reputation services that list IP ranges that have no business sending unauthenticated direct-to-MX, such as Spamhaus’ Policy Block List (PBL).
Recording the volumes of outbound port 25 traffic from particular users — a sharp increase from the historical trend can indicate infection.
Monitoring blocked attempts to use port 25 to outside MTAs [message transfer agents] — another indication of infection.
Moving infected PCs into a "walled garden," which prevents them from sending email, surfing the Web, or using other Internet applications until the problem has been cleaned up.
These are all good ideas, and far too few ISPs implement any of them. In short, South Korea's move may sound dramatic, but the Internet and Security Agency is just proposing a step that most ISPs already took years ago... and has proven to be woefully inadequate. We need far more.