go to
Configuration | Policy Management | Traffic Management | Assign Rules to Filter
highlight public and select "assign rules to filer"
highlight everything except IKE/IPSEC related rules and hit remove..
just be sure to leave GRE if your using PPTP and L2TP if your using that.
not http/https rules should be allowed via the public filter (which corresponds
to the public interface)
private interface will always allow everything..so dont worry about it.