You can enable different types of services on parent
and child devices. For example, to increase throughput, add more
child devices, enable all their services and allow the child devices
to scan traffic and provide EUQ services.
You can deploy IMSS devices
in a parent/child group in either deployment scenario. However,
if you enable the scanner service on parent and child devices, you
must use the same type of deployment for all devices in a single
group. You cannot deploy some child devices at the gateway and others behind
the gateway.
In addition to the above SMTP-scanning scenarios, you might want IMSS to
scan POP3 traffic. See Understanding POP3 Scanning for more information.