Chris Spak wrote:
>
> We would like to implement a "authorized sender" capability, this
> would allow our customer to only receive email from people that they
> have on their white list.
>
> If the incoming message is from someone not on a receiver's white
> list then the system would save the email message for 48 hours and
> send the sender an
>
> email form to complete. The sender would need to enter their name
> and email address. If the sender responds, the response is then sent
> to the receiver for approval to add this person to the white list and
> allow the message waiting and future messages to pass through to the
> receiver.
What you're talking about is called challenge/response, and is widely
considered to be a very bad idea. For the most recent discussion on the
topic, please read the thread rooted at:
http://www.exim.org/mail-archives/exim-users/Week-of-Mon-20050321/msg00030.html
- Marc
