Short description of Live Email Validation Component 2.4: "The Email Validation Component is a true native, 100% managed C# component that can be implemented for both Webform and Winform."
Email Validation Component does:
1. An accurate syntax check
2. A domain check by looking up MX records
3. A username test using SMTP
We've packed a full set of solid, professional networking code into a simple component. With only one method call.