I would recommend you install Pflogsumm and configure it to send you a daily report via email about Postfix activity. A report from Pflogsumm will have the info that your client seeks (and lots more) that you should be aware of as well.
I would recommend you install Pflogsumm and configure it to send you a daily report via email about Postfix activity. A report from Pflogsumm will have the info that your client seeks (and lots more) that you should be aware of as well.