This is the only offered solution which can provide this functionallity, this component extract all MX records of certain doman. MX record is the address of email server.

Without this component, you have to get the records manually using nslookup utility, or using some free web service like zonedit, put you cannot integrate it with your code.

Features:

Retrieve all MX records of provided domain
This component uses windows sockets and do not need any other software like Internet Explorer, Outlook, Windows Server...

• EmailValidator.Net 1.0.0
  Check email addresses without actually sending an email. check MX records, smtp, syntax, mailbox ... With only one method call Email Validator.Net component will solve all your...

• 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

• DNS MX Wizard ActiveX 3.0
  DNS MX Wizard is an ActiveX control that lets you query a Domain Name System (DNS) server for Mail Exchange(MX) Resource Records(RR). MX RR's contain the name of the server responsible for handling mail for a domain. Multiple resource records can...

• Easy Slide Show flash component 1.1.3
  Easy Slide Show flash component is intended for simply designing slide show and supports flash mx and flash mx 2004 authoring tools