too long

I have a one mailing script which are run perfect right now . Using .csv we need fetch all email address on that and send one by one mail automatically.

Which script are run as sending mail to multiple user email address.

Now i want to create one extra feature on that "BOUNCE BACK MAIL" . When email sending script is working at that time which email address not send mail . i want to generate bounce email log generator in .txt file or other file.

Is there any script related this requirement .

Thanks in advance.