Older SEP 11.06 Allow All Other IP Traffic Firewall Rule

I'm looking for information on the default firewall rule set for SEP version 11.06.  We are in the process of migrating to 12.1, and using the firewall policies for that version.  So going forward it shouldn't be an issue. However the question is: What was the purpose of the "Allow All Other IP Traffic" rule?  It was enabled by default, and was followed by a Block All Other Traffic rule, lower in the stack. 

There has been concern that systems running this firewall rule may have been unprotected from network threats, and we are trying to better understand the purpose of this rule...and the impact to client systems.  Also what is the impact of disabling this setting?  Any information would be appreciated.  Thanks