In article <115t1cdk5p2u146@news.supernews.com>,
Paul Vader <pv+usenet@pobox.com> wrote:

>In one of my more paranoid moments, I wondered whether it was possible to
>sneak data to a server via connection attempts, when then appears to
>reject them. Thinking about it again after I saw your message, it should be
>possible, and not even all that difficult. Fortunately, I think it would
>only work in one direction, unless ... OK, I'm stopping now. *

Spammers already know about portknocking.

Seth