Obtaining definitions when a new, emerging threat is discovered
You can use Rapid Response when you need quick responses to emerging threats. Rapid Response definitions are most useful for a perimeter defense to mitigate quickly spreading threats.
Rapid Response definitions do not undergo the same rigorous quality assurance testing as LiveUpdate definitions. Symantec encourages users to rely on the full quality-assurance-tested definitions whenever possible. Ensure that you deploy Rapid Response definitions to a test environment before you install them on your network.
When you enable Rapid Response virus definition updates, Symantec Messaging Gateway uses the Symantec Web site as the source for definition updates by default. But you can modify the source to a LAN host.