nmanousos/email-existence — pull request #5 by kunev (2013-01-04 07:26:01+00:00)
Title: Several improvements

I've made several additions that might be useful:

* Doing a simple regex check before starting a connection
* Handle MX lookup failures
* Send full HELO message when making a connection, since some servers don't respond otherwise.
* Handle various connection issues(timeout, connection refused etc.)
* Added an `undetermined` argument to the callback, since you might want better distinction between a definitely non-existent email and one that can not be verified.

P.S.: I apologize for the sloppy pull-request, I wasn't planning on sending you one when I created the fork.