diff --git a/sbin/ipmon/Makefile b/sbin/ipmon/Makefile
index d900f6754f73..de743322c379 100644
--- a/sbin/ipmon/Makefile
+++ b/sbin/ipmon/Makefile
@@ -6,7 +6,9 @@ PROG=	ipmon
 MAN=	ipl.4 ipmon.8
 SRCS=	ipmon.c
 
-CFLAGS+=-DUSE_INET6 -DIPL_NAME=\"/dev/ipl\" -I${.CURDIR}/../../contrib/ipfilter
+CFLAGS+=-DUSE_INET6 -DIPL_NAME=\"/dev/ipl\"
+CFLAGS+=-I${.CURDIR}/../../sys/contrib/ipfilter
+CFLAGS+=-I${.CURDIR}/../../contrib/ipfilter
 WARNS=	0
 
 MAINTAINER=	guido@freebsd.org