since yesterday I had email problem so I was keep sending email for test purpose, I don't think the total was more than 200 email.
however today I could fix it after all by putting the correct hostname but now one of my box keep receive this email for more than 4000 times in last one hour:
This is the Postfix program at host host2.persiasys.com.
I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.
For further assistance, please send mail to <postmaster>
If you do so, please include this problem report. You can
delete your own text from the attached returned message.
The Postfix program
<email@example.com>: Host or domain name not found. Name
service error for name=localhost.localdomain type=A: Host not found
Reporting-MTA: dns; host2.persiasys.com
X-Postfix-Sender: rfc822; firstname.lastname@example.org
Arrival-Date: Sun, 7 Jan 2007 17:08:07 +0800 (MYT)
Final-Recipient: rfc822; email@example.com
Diagnostic-Code: X-Postfix; Host or domain name not found. Name service error
for name=localhost.localdomain type=A: Host not found
Subject: Mailsize: web6_root
Sender: S. Mohammad add
Date: Today 10:08