We have installed the ZCS in the customers site 2 days back.... Now all the outgoings are bouncing back with the below messages.

"This is the mail system at host rafgi-mailsrvr.alrafaallc.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 mail system

<prasanth@alnahlatech.com>: host alnahlatech.com[] said: 550 5.7.1
Rejected by Endpoint Reputation check. (in reply to MAIL FROM command)

I had contacted ISP and they had commented as follows.

"Root cause is, customers network has one or compromised machines which are sending spam outside. They need to clean the machine, develop a network security where only the mail server is authorized to send on port 25 and other machines donít have this access."

Bu t Ihad the security product implemented in the site (sonic wall which is protecting the Incoming and outgoing spam"...

This is the thrid time am getting this messages and calling to ISP for rectifying the same.

Is this particular bouncing back issue is something related to relay configuration in the mail server.

Please help to solve this isseu and advance thanks for doing that.

Thnaks and rgds,