SMTP testing without sending out mail

October 2, 2008 00:05 by author

A few weeks ago I was working on a rather large system that was still quite the black box to me. I was trying to get it to run when I suddenly realized it had been sending out error reports for about 20 or 30 minutes, at a rate of a few per second. One of my co-workers received over a 1000 of these e-mails. That brought up the issue of how I would test without having the system send out all those mails. And just turning off the local SMTP server wasn't an option either. So I set about finding an alternative that would allow me to continue testing without having to worry about mails being sent out blindly. I found some solutions that required me to integrate assemblies into my .NET solution, but this was not practical at the time. Finally I found something that suited my requirements. The little program that came to the rescue is called DevNull. It runs independently of your system, and "catches" any mails that are sent via SMTP. It has the option of saving the e-mails on your hard drive so you can view them later. And that was perfect for what I needed. So if you need to test an application that send out e-mails without the mails actually going out, then DevNull is perfect for you.