On Monday 26 May 2003 16:33, Andrew Shore wrote: AS> One "technical" solution that would discourage spam would be to AS> add a key (a text string, for example) to the email header. The AS> user gives out their email address with different keys to AS> different groups of people; if a key attracts spam, all they AS> have to do is stop accepting mail with that key. It would also AS> make organising mail very easy. On the negative side, the extra AS> complexity might prove challenging for some... Multiple keys is too much like hard work. Dan Kohn can probably tell you about the single text-string key in mail headers promoted by http://www.habeas.com/ ... What about some form of reverse verification via SMTP? After you receive a mail, the receiver could open up a separate SMTP/TCP connection back to the purported sender, asking 'did you send me this' and asking for some sort of verification from logs? Might cut down on spoofing; possibly better than the minimum reverse lookup, since it distinguishes spoofed from passed-through content, and gives you a tighter audit trail of sorts. L. <http://www.ee.surrey.ac.uk/Personal/L.Wood/><L.Wood@ee.surrey.ac.uk>