How to encrypt trafic between Cisco CES and On premise ESA

[B. BELHADJ]

Dear all

For a new project of migrating our Secure Email Gateway from Cisco ESA to Cisco Cloud Email Security we will in first time keep our On-Premise ESAs as a gateway for Outbound and Inbound to and from the CES.

Sender or Recipient <=======> Client_Internal_Network <==> Cisco Ironport ESA <======= Communication =======> Cisco Cloud CES <=======> Sender or Recipient

My question is how we can secure the tunnel between our ESAs and CES Cisco Ironport ESA <======= Communication =======> Cisco Cloud CES?

Configuring SMTP route with 587 port can be the solution?

Best regards

[dangolds]

Under Network, SMTP Routes, configure your mail domain(s) pointing to your premise IP firewall port 25 (forwarding to your Exchange server). Under Mail Policies, Destination Controls, add an entry for that IP address with the TLS setting you prefer.

For setting up TLS generally, please see:

Comprehensive Setup Guide for TLS on ESA - Cisco