diff --git a/tests/sys/netpfil/common/Makefile b/tests/sys/netpfil/common/Makefile
index 189b8b44cfce..5ea3e7d9b687 100644
--- a/tests/sys/netpfil/common/Makefile
+++ b/tests/sys/netpfil/common/Makefile
@@ -1,28 +1,31 @@
 # $FreeBSD$
 
 PACKAGE=	tests
 
 TESTSDIR=	${TESTSBASE}/sys/netpfil/common
 
 
 ATF_TESTS_SH+=	\
 		dummynet \
 		pass_block \
 		nat \
 		tos \
 		fragments \
 		forward
 
+# Tests reuse jail names and so cannot run in parallel.
+TEST_METADATA+=	is_exclusive=true
+
 ${PACKAGE}FILES+=	\
 		utils.subr \
 		runner.subr \
 		pft_icmp_check.py \
 		pft_ping.py \
 		pft_synflood.py \
 		sniffer.py
 
 ${PACKAGE}FILESMODE_pft_icmp_check.py=	0555
 ${PACKAGE}FILESMODE_pft_ping.py=	0555
 ${PACKAGE}FILESMODE_pft_synflood.py=	0555
 
 .include <bsd.test.mk>