An engineer is configuring Cisco WSA and needs to enable a separated email transfer flow...

To enable a separated email transfer flow from the Internet and from the LAN, the engineer must use the two-interface deployment mode on the Cisco WSA. This mode allows the WSA to have two separate network interfaces, one for the Internet traffic and one for the LAN traffic. This way, the WSA can apply different policies and settings for each interface, and isolate the email flows from each other. The two-interface mode also provides better performance and security than the single-interface mode, which uses only one network interface for both Internet and LAN traffic12. The other deployment modes, such as multi-context, transparent, or single-interface, do not support a separated email transfer flow from the Internet and from the LAN. References:

Two-interface mode, section “Deployment”.

WSA network configuration, section “Interfaces”.