Comcast’s smtp disconnects ineffective

Back on May 24th I wrote about Comcasts plan to combat spam originating on its network. Comcast reported that they planned to terminate the ability of some users to send mail out via port 25. Unlike Cox Communications who turned off port 25 for all customers forcing them to use Cox’s SMTP server, Comcast only did this to users who appeared to be used to send high amounts of spam. reports that spam from Comcast has dropped 35 percent since that time.
The article played it evenly, but I felt that Comcast was trying to trumpet this as a great victory. To my way of thinking that it only dropped 35% shows that targeted disconnects are effective or aren’t being done aggressively enough. Comcast should just do what the other major providers have done already. Cut off port 25 to all. That will stop 100% of the Comcast spam, not just 35% of it. If they want to be nice, they can then turn 25 back on for the people who really need it.
As a disclaimer, my ability to send mail outbound not using Cox’s server has been cut off by Cox. At the time, I didn’t like it. But now, I think its just good internet citizenship. Too many trojaned home systems are spewing forth spam. Its got to stop.