Bulk Email Validator

[Lopar]

I wish to either make use of a freely available email validator (software, script or online service). If this does not exist, are there some free PHP classes that I can make use of to validate email addresses? I have about 100 emails and before I send to these emails I would like to check their validity. I don't want my server to be blacklisted because of bounce backs.Please note, I am not looking for just a a syntax checker. I am talking about DNS and SMTP validation.The ideal solution would be a pHP script or the like that I can setup locally or on my server.Thanks all for any help