Create a service that can recieve email from windows SMTP service determine who it is from by checking this against a db. If the email is from an allowed source then forward it on to the recipient.
If it is from an unknown source, repy to the sender, adding a message containing a graphical number sequence to the start of the email and store the email in sql server.
The sender needs to reply to this email quoting the number from the graphic in the first line cause the original mail to be sent to its final destination.
If the correct response is not recieved within a specified timeframe, then the email is deleted.
This needs to be multihtreaded and able to accomodate multiple domains. Users can view/edit their pending mail queues via a web browser.
1. This project is to run on a stand alone server
2. It's function is to eliminate spam by sitting between the sender and the recipient's mail server.
3. It will verify the sender was a human or allow the mail to pass by checking against user maintained white/black lists.
3. It must be able to handle multiple domains for different end user destinations. i.e. forward customers mail on to their own different mail servers after verification. These 'final mail destination' addresses may be IP addresses or domain names
4. It must run as a service
5. It must be able to process multiple emails at once.