Explanation/Reference: https://sc1.checkpoint.com/documents/R77/CP_R77_Mobile_Access_WebAdmin/82201.htm

Reference: https://sc1.checkpoint.com/documents/R76/CP_R76_ClusterXL_AdminGuide/7290.htm

These are the types of Automatic Reactions:
Mail - tell an administrator by email that the event occurred. See Create a Mail Reaction.
Block Source - instruct the Security Gateway to block the source IP address from which this event was detected for a configurable period of time . Select a period of time from one minute to more than three weeks. See Create a Block Source Reaction Block Event activity - instruct the Security Gateway to block a distributed attack that emanates from multiple sources, or attacks multiple destinations for a configurable period of time. Select a period of time from one minute to more than three weeks). See Create a Block Event Activity Reaction.
External Script - run a script that you provide. See Creating an External Script Automatic Reaction to write a script that can exploit SmartEvent data.
SNMP Trap - generate an SNMP Trap. See Create an SNMP Trap Reaction.

Explanation/Reference:
Reference: https://sc1.checkpoint.com/documents/R76/
CP_R76_PerformanceTuning_WebAdmin/6731.htm