how can I see the emails sent by my web server(netregistry) ?
They are actually sent through a php script. Is there a way to keep track of them ?
i search it but didn't find any solution
The standard answer for questions along the lines of "How can I see what my program is doing?" is logging. Write some sort of record of the emails you send (for instance the time, address, and subject, or whatever else you need) to a file. There are powerful logging utilities available, but at its most basic, you can just write what you want to a file like any other data. To count how many emails you've sent, simply count the number of lines in the file (assuming you log one line per email).
For the specific case of email, an alternative would be to actually send the emails to yourself as well as the intended recipient. You can just add yourself as another recipient in the to field, or BCC yourself if you don't want the intended recipient to know you also received the email.