Possible Duplicate:
check if email are valid and exists
How to validate an email address in PHP
I am developing a application for sending mail by provided mail address in PHP. now i wanna validate given mail address is really exist in domain or not
**i.e
abc@xyz.com (for example its registred in xyz domain)
abcd@xyz.com (for example its nod registred xyz domain)**
how can i verify it by using PHP.
Thanks in advance