Question

Unfortunately my hMailServer can’t send emails to Hotmail. How can I determine whether a given email address is Hotmail or not, to prevent the message from being lost.

Hotmail e-mails can be:
* @live.com
* @live.fr[pt][ru][etc]
* @hotmail.com,
* @live.com.jp
* @msn.com
* and many country TLD specific combinations involving MSN, Hotmail and Live.

It seems like it’s impossible to use a regular expression to filter that.

Any ideas on how to detect whether an email addresses is in the Hotmail family of addresses?

Answer 1

This will work:

function bool IsHotmailAddress(string email) {
    var r = new Regex(@"\@(live|hotmail)\.[a-z]{2,3}(\.[a-z]{2,3})?$", RegexOptions.IgnoreCase);
    return r.IsMatch(email);
}