I had planned on using an open source SMTP server as a base and adding new features in to do whatever parsing I need and then send the response but I’m wondering if there is an even easier way to do this.
Is rolling my own SMTP server my best option or is there an easier way for me to do this?
I would prefer to use .NET to do this.
Accomplishing this with the built-in .NET libraries is relatively simple.
The place to start would be to write a program to download the mail: here’s a great example using POP3/C#.
Once you have that you can parse/store the e-mail contents using regex or whatever rules engine you’re building and then use .NET smtp libaries to send out your responses.