Currently one of our customers must fulfill their auditors need to have multi-layer security devices in their environment, including Secure Email Gateway (SEG). Their current environment is using Cisco IronPort and after some discussion they planned to purchase Proofpoint as their second SEG.
Their plan is to put Proofpoint in front of their IronPort. Now will it be a problem for IronPort since Proofpoint will forward the emails to IronPort because Proofpoint IP is internal and internal IPs are always trusted? We have the same problem when we put Proofpoint behind IronPort but we configured Proofpoint to examine one IP hop (skipping IronPort) to look at the senders Public IP. Is there any similar configuration on IronPort?