miniRelay

miniRelay is a small application that simulate a SMTP mailserver on any computer using the 'localhost' IP address. This program will allow you to send emails directly to the recipient's email server without using your own ISP email server, thus bypassing any limitation that this normally imposes. This application also allows you to perform end to end testing of any code that involves sending emails, but without having to use your production email gateway. Next to that, if you have difficulty finding an available SMTP server, this application will be very useful.

miniRelay is really easy to use and configure. By default, the application will connect to the SMTP port (25) on the localhost IP address (127.0.0.1), but you can change the listening port with just a few clicks. Once set, you will be able to send emails within your local network and to the outside over internet. Since the application is really small and it uses techniques to send mail that appear to be similar to some viral activities, some antivirus software mark is as a virus, but it is completely clean.