diff --git a/tests/sys/netpfil/common/utils.subr b/tests/sys/netpfil/common/utils.subr
--- a/tests/sys/netpfil/common/utils.subr
+++ b/tests/sys/netpfil/common/utils.subr
@@ -87,6 +87,9 @@
 		if ! kldstat -q -m ipfw; then
 			atf_skip "This test requires ipfw"
 		fi
+		if [ $(sysctl -n net.inet.ip.fw.default_to_accept) -ne 1 ]; then
+			atf_skip "ipfw tests assume net.inet.ip.fw.default_to_accept=1"
+		fi
 	elif [ ${firewall} == "pf" ]; then
 		if [ ! -c /dev/pf ]; then
 			atf_skip "This test requires pf"