CAS is integrating with Symantec Mail Gateway (SMG).
SMG is sending email to be scanned by CAS and when it trigger the alert, the notification does not have the Client IP and Server IP information in the alert notification as shown below where it shows 'Unknown' for both values.
The behavior seeing is expected because SMG is not able to send the Client IP and Server IP information to CAS, thus the information unable to be populated by CAS.