> majority of spam emails are using forged addressing, propose that receiver smtp > server connect to the sending server and see if the server bounces on that users > address. I'm doing this now for one user community, with mixed results. In particular, I'm surprised at the number of users whose email addresses are valid (in that if you send them mail, it will get there eventually), but for whom attempts to validate their addresses via SMTP fairly consistently fail for temporary reasons (e.g. DNS timeout, SMTP doesn't respond, SMTP returns 4xx). Keith