Enable support for inspecting and processing Generic Routing Encapsulation (GRE) packet headders. Only needed if you are monitoring GRE tunnels.

Packages describing “gre” as local USE flag

Package “gre” Flag Description
net-analyzer/snort Enable support for inspecting and processing Generic Routing Encapsulation (GRE) packet headders. Only needed if you are monitoring GRE tunnels.
net-analyzer/barnyard2 Enable GRE support

All packages providing a “gre” USE flag (1)