Testing e-mail functionality in your Microsoft Dynamics AX/GP application/customization using external e-mail servers has always been a frustrating process. If your test e-mail somehow avoids anti-spam and other SMTP server services, it will still take several minutes to receive. Sometimes, it can take 5 – 10 minutes for your sent e-mail to arrive at the destination - and you can never be sure if your test e-mail is late or if delivery has failed due to an error in your application.
Wouldn't it be great to have a mock application that pretends to be a SMTP server and shows you what you sent immediately? That is exactly what SMTP4DEV does.
SMTP4DEV is free and you can download it from CodePlex at http://smtp4dev.codeplex.com. All you have to do is unpack and run, and make sure your mock SMTP server is listening.
Once you have SMTP4DEV running and listening, you can use the sample C# code to send an e-mail to your mock SMTP server. Notice the From and To e-mail addresses; they can be anything.
Execute the sample C# code and your test e-mail will immediately show in SMTP4DEV.
Now stop listening on port 25 and execute the same sample C# code again. Since SMTP server is no longer available, SmtpClient will throw an exception.