macro.gre

sharewall is very good

#
# Shorewall version 4 - GRE Macro
#
# /usr/share/shorewall/macro.GRE
#
#	This macro (bi-directional) handles Generic Routing Encapsulation
#	traffic (RFC 1701)
#
###############################################################################
#ACTION	SOURCE	DEST	PROTO	DEST	SOURCE	RATE	USER/
#				PORT(S)	PORT(S)	LIMIT	GROUP
PARAM	-	-	47	# GRE
PARAM	DEST	SOURCE	47	# GRE
#LAST LINE -- ADD YOUR ENTRIES BEFORE THIS ONE -- DO NOT REMOVE