One of the basic problems with discussions about spam control is that it focuses entirely on spam. Blocking output SMTP from individual dial-ups has a serious negative consequence:

Laptop mobile users cannot use their home SMTP server.

in the business, we call this "tough noogies."

At best, they must reconfigure for each venue -- goodbye wireless hotspot convenience -- and that is IF they know the SMTP server address for the local access.

i've gotten very good mileage out of ssl-smtp, and out of "port forwarding" so that my laptop uses 127.0.0.1:25 for outbound mail, which is actually a (ssh-borne) tunnel to my home smtp server.

In other words, by blocking output SMTP, mobile users are hurt badly. I know that *I* certainly am. Constantly and serously.

yes. let me take this opportunity to thank you for your significant contributions to smtp and of course rfc822. i'm sorry that you have to be hurt now. but the design calls for a polite population, and while that was true of the internet in 1983, it is absolutely not true today. the nonpolite nature of the overall population means that you will have to be hurt and you will have to change how you use mail in order to make the pain stop. there's a slight choice on the pain menu -- you can have (A) an unusable mail system clogged with unwanted traffic such as spam and viruses, or (B) a barely-usable mail system where everything you want to do is less convenient because you have to use ssl-smtp and ssh tunnels. either way you have to be hurt now. and that saddens me, it really does.