Default email X-header applied by DLP Network Prevent for Email server and viewable from packet capture.
Modified email X-headers are not viewable from a packet capture and mail is not blocked downstream because of the missing header information.
SMTPPrevent_Operational log errors:
Peer disconnected unexpectedly
Message not accepted by forwarder
4.4.2 service timed out.
RequestProcessor log errors:
Caused by: java.net.UnknownHostException: SERVERNAME: unknown error
at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method)
The DLP Network Prevent for Email server failed to resolve it's own hostname through java.net.InetAddress.getLocalHost().
Add the DLP Email Prevent IP and Hostname to /etc/hosts to resolve the issue.