Index: sys/net/ipfilter/Makefile
===================================================================
RCS file: /home/dcvs/src/sys/net/ipfilter/Makefile,v
retrieving revision 1.3
diff -u -r1.3 Makefile
--- sys/net/ipfilter/Makefile	28 Jul 2004 00:22:37 -0000	1.3
+++ sys/net/ipfilter/Makefile	18 Dec 2006 23:00:41 -0000
@@ -4,13 +4,19 @@
 .PATH: ${.CURDIR}/../../contrib/ipfilter/netinet
 KMOD=	ipl
 SRCS=	mlfk_ipl.c ip_nat.c ip_frag.c ip_state.c ip_proxy.c ip_auth.c \
-	ip_log.c ip_fil.c fil.c
+	ip_log.c ip_fil.c fil.c opt_inet6.h
 NOMAN=
-.if !defined(NOINET6)
-CFLAGS+= -DUSE_INET6
+
+# XXX:  Building this outside of a buildkernel with a kernel that does not have
+# INET6 is not supported since the module will complain about undefined symbols.
+.if !defined(BUILDING_WITH_KERNEL)
+opt_inet6.h:
+	${ECHO} "#define INET6   1" > ${.TARGET}
 .endif
+
+CFLAGS+= -include ipf_inet6.h
 CFLAGS+= -DIPFILTER_LKM -DIPFILTER_LOG
-CFLAGS+=  -I${.CURDIR}/../../contrib/ipfilter
+CFLAGS+=  -I${.CURDIR}/../../contrib/ipfilter -I${.CURDIR}
 #
 # If you don't want log functionality remove -DIPFILTER_LOG
 #
Index: sys/net/ipfilter/ipf_inet6.h
===================================================================
RCS file: sys/net/ipfilter/ipf_inet6.h
diff -N sys/net/ipfilter/ipf_inet6.h
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ sys/net/ipfilter/ipf_inet6.h	18 Dec 2006 22:38:39 -0000
@@ -0,0 +1,8 @@
+/* $DragonFly$ */
+/* This file uses the kernel config to determine if IPV6 should be used. */
+
+#include "opt_inet6.h"
+
+#ifdef INET6
+#define USE_INET6	1
+#endif