> > I would think this stat would be difficult to come by since a lot of > > smtp servers don't return a name or version in the smtp header for > > security reasons. > > Yah, I just imagined someone would have done a study. I've seen numbers like > 70% sendmail but don't know how accurate that is. Someone has, but it's not publicly available. The 70% is not accurate. Despite being out of date, the numbers presented at http://www.ohse.de/uwe/surveys/smtpauto.html show a trend worth paying attention to. Also note the sampling method is reasonable. Andy