Sending e-mails from the cloud based web application

This sounds crazy. But when you move your website to the cloud, you get problems in things you were previously taking for granted. Like sending e-mails. Basically, the problem is that many e-mail servers, usually ones of big providers, have Azure, Amazon and other cloud provider IPs blacklisted. When you attempt to use SMTP service from your virtual machine in Azure – in many cases it fails to deliver. This means, that your Azure machine can not act as mail server and shouldn’t attempt to deliver messages to recipient SMTP server directly.

Why would you use SMTP service at all? Well, mainly for the sake of performance. Your web application, be it ASP.NET, PHP, Ruby or whatever, will benefit from saving the outgoing e-mail message as text file somewhere on local hard drive, instead of trying to deliver it using TCP/IP, even if that’s done in asynchronous method.

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