How to check if an email address exists without sending an email?

[ansriharsha]

Hi all, How to check if an email address exists without sending an email without using a third party control. Thanks and Regards, sriharsha

[Michel Godfroid]

You can't. Note that sending an email offers no guarantee either. I use a black hole setup on all my mail servers, and I never reject a mail. I just throw them away.

[JHizzle]

Not possible really, the best you can do is use regular expression to validate that the format of the address provided is valid.

[ansriharsha]

regular expression will only validate the email address format,which we are using, but we want to validate the email address exixtence or atleast domain existence. i.e to chekh if the user has mentioned a valid email id or not, and then send a email based on that. thanks and Regards, sriharsha

[JHizzle]

ansriharsha wrote:

regular expression will only validate the email address format,which we are using,

Right, which is what I said. I don't think you're going to be able to do this without sending a test email int eh first place which defeats the purpose of the exercise. Your other option is to strip the domain out, do a webrequest to it on the assumption that they have a website set up on it. If so, better chance that the email address is valid, if not, it's a dud.

[The Man from U N C L E]

Well that lets bogus hotmail addresses though for starters. And I work at an office where we have a .co.uk email address but a .com web site (historical nightmare, don't ask).

If you have knowledge, let others light their candles at it. Margaret Fuller (1810 - 1850) [My Articles]  [My Website]

[JHizzle]

Sadly so, hence the disclaimer "better chance" :)

[suwangsoft]

public static bool IsEmail(string Str) { bool v = false; if (Str != null && Str.Trim() != "") { Match m = Regex.Match(Str, @"\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*"); if (m.Success) { if (Str == m.Value) { v = true; } } } return v; }