Hi folks, I've been using howtoforge's tutorials for a long time and its great (Thank You). Now I find my self in a nasty situation where I have an email server that I use it to send mass emails with newsletters. My problem is that, even that I filter the database for valid or non-valid email addresses, with some php scripts I developed, in the database that I have, it takes a long time which is the thing that I don't have. So, I have to send the newsletter to all the email addresses I have (valid or not), and that generates lots of Email Delivery Errors. Now I am looking for a way to filter those non valid emails through postfix or some app, and save them in a file so I can later compare them. So there goes my question: Are there any logs/apps that contain those Email Delivery Errors? Thank you, w0rldart PS: Hope I was clear, if not, I will give my best to explain better next time.