Hi
You could add the "exists" mechanism after all your accepted smtp-servers
and log detailed DNS-queries for it (see host -t txt altavista.com). So
you have a list of potential IPs your user used to send emails. You can
present this list to your user: "look, these are the IPs trying to send
email pretending to be you. Is that really you?". And all the user has to
do is to accept the IPs or not.
Too complicated. I was thinking of a mailadress customers would simply send a
mail to and automagically parsing out the headers with all mailservers. The
only remining thing we would have to take care of is that they're not using
our webmail to send this validation-mail :)
--
Kind Regards
Daniel Lorch
System administration
Hostpoint GmbH | The Data Residence |
Zürcherstrasse 2 | 8640 Rapperswil | Schweiz
Tel +41 55 220 0404 | Fax +41 55 220 0409 | www.hostpoint.ch