O servidor SMTP, embora anteriormente incluído no IIS, não era suportado pela equipe do IIS. Por qualquer motivo, a equipe proprietária da Microsoft decidiu retirá-lo do Vista, apenas incluindo-o no Server 2008.
Portanto, você precisa de um produto de terceiros. Uma boa e simples substituição é o Servidor SMTP gratuito :
Free SMTP Server is a SMTP server program for Windows that lets you send email messages directly from your computer. It's very simple but very useful for laptop users traveling around the world and connecting their PCs to different Internet Service Providers in different countries. You can use it instead of ISP's SMTP server to increase your security and privacy. Free SMTP Server supports all email programs like Outlook Express and Eudora, but best optimized to work with Outlook Express. The email program you already use for sending and receiving messages can be connected to the server in a very easy way - by using the word "localhost" instead of your current SMTP host. Having done so, you can send messages in a usual manner. Free SMTP Server is very fast, while sending, it establishes dozens of SMTP connections, and gets the most out of your Internet connection. The user interface of the program is very easy to learn, excellent documentation is included. The program is freeware so there is no reason not to download and try it!
