how to check if a given email address actually exist in c# ?

Question

Hi, I am building a C# application where users creat an account and type their email address, I know how to validate it with Regular expression, what I am having truble with is how to check if that email actually exist? i.e. [email protected] --> is there such email address?

Thanks!

Answer 1

There's only one way to do that: Send an email containing a (unique, of course) link to the address, and ask the user to click the link.

Answer 2

The only way to check this is to send an email to that address and make sure that you send a link that needs to be clicked to activate the account. There is no other way to check if an email is correct

Answer 3

Have a look at EmailVerify.NET

EmailVerify.NET is a powerful Microsoft .NET software component that verifies e-mail addresses with various tools, including:

• Advanced syntax verification, according to IETF standards (RFC 2821 and RFC 2822, among others)
  • DNS validations, including MX record(s) lookup
  • Disposable e-mail address (DEA) validation
  • SMTP connection and availability checking
  • Mailbox existence checking, with greylisting and temporary unavailability support
  • Catch-all testing

Answer 4

If you wanted to be really fancy you could embed an image in the email as-well. When your server detects that the image was downloaded then you know they opened the email. This also removes the need for the clicking a link thing which many people either don't trust or it doesn't work. Just a thought.