At a short notice I had to use C# to send out bulk emails to a few thousand recipients. Of course short notice is not the problem of the problem. To keep things interesting I couldn't use our company's Exchange Server and the domain email address, which would have been straight forward. All I would have to do is write code to send emails through this server. But that was not going to happen. I had to use our department's domain name which is different from the company and there were no email servers setup nor were there any email addresses created for this domain. So the problem is four fold.
1. Write C# code to send individual html formatted emails with a plain text option, from a html template file with images in the email and a 6MB PDF attachment to boot.
2. Setup a server and find viable mail server software to create email addresses, send and receive emails for the domain in question.
3. Set up the DNS entries including the MX records and SPF record to avoid the emails being rejected or avoid the dreaded SPAM folder especially in the case of Hotmail and AOL.
This tutorial is divided into 3 parts each dedicated to an individual step from above. Let's start off the C# code.
1. Sending bulk emails with C# and Windows 2003 POP3 Server: Part 1 of 3 - C# Code
2. Sending bulk emails with C# and Windows 2003 POP3 Server: Part 2 of 3 - POP3 Server Setup
3. Sending bulk emails with C# and Windows 2003 POP3 Server: Part 3 of 3 – DNS, MX and SPF Records
Let’s get started: Part 1