Secondary Interface FAQ

Cisco Secure Email Cloud Gateway

What is the purpose of having a second interface on the CES (Email Security Appliance)?

  • In case you are configuring Microsoft Office365 or G-suite with the Cisco Cloud Email Security Appliance, it is important to have a second interface that will be mapped to a separate MX record. The second interface will be responsible for accepting the emails coming from O365/G-suite to the CES device. You may request it if not already configured.

How to request a secondary interface?

Why a secondary interface is required?

  • The secondary interface is required to segregate the traffic from incoming to outgoing.
  • This interface will be responsible for handling outbound emails only.
  • Using this interface, you can create a separate outbound listener, so that you can route your outgoing emails through CES from O365/G-suite ensuring your traffic is independent of the incoming and there are no routing issues.

How you can configure G-suite?

How you can configure O365?



The maximum number of interfaces and listeners that can be assigned on the devices is two.

Three or more interfaces/listeners are not supported on Cisco Secure Email Cloud Gateway devices.