Simple step to stop backscatter on cPanel server

To prevent backscatter you have to done following modifications:

• Apache SpamAssassin™: bounce spam score threshold has to be set to “No bouncing by spam score default”
• Enable Greylisting
• Exim – Sender Verification Callouts should be disabled
• Exim – Allow DKIM verification for incoming messages should be enabled
• Exim – Allow DKIM verification for incoming messages should be enabled
• Exim – Reject DKIM failures should be enabled
• Initial default/catch-all forwarder destination should be set to Blackhole

This can help prevent the SPAM from reaching your server, and thus reduces the bounce messages.