diff --git a/tests/sys/netpfil/pf/killstate.sh b/tests/sys/netpfil/pf/killstate.sh
index ec01910f0867..b3d94a245548 100644
--- a/tests/sys/netpfil/pf/killstate.sh
+++ b/tests/sys/netpfil/pf/killstate.sh
@@ -1,458 +1,518 @@
 # $FreeBSD$
 #
 # SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 #
 # Copyright (c) 2021 Rubicon Communications, LLC (Netgate)
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions
 # are met:
 # 1. Redistributions of source code must retain the above copyright
 #    notice, this list of conditions and the following disclaimer.
 # 2. Redistributions in binary form must reproduce the above copyright
 #    notice, this list of conditions and the following disclaimer in the
 #    documentation and/or other materials provided with the distribution.
 #
 # THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 # ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 # ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 # FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 # OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 # HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 # OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 # SUCH DAMAGE.
 
 . $(atf_get_srcdir)/utils.subr
 
 common_dir=$(atf_get_srcdir)/../common
 
 atf_test_case "v4" "cleanup"
 v4_head()
 {
 	atf_set descr 'Test killing states by IPv4 address'
 	atf_set require.user root
 	atf_set require.progs scapy
 }
 
 v4_body()
 {
 	pft_init
 
 	epair=$(vnet_mkepair)
 	ifconfig ${epair}a 192.0.2.1/24 up
 
 	vnet_mkjail alcatraz ${epair}b
 	jexec alcatraz ifconfig ${epair}b 192.0.2.2/24 up
 	jexec alcatraz pfctl -e
 
 	pft_set_rules alcatraz "block all" \
 		"pass in proto icmp"
 
 	# Sanity check & establish state
 	# Note: use pft_ping so we always use the same ID, so pf considers all
 	# echo requests part of the same flow.
 	atf_check -s exit:0 -o ignore ${common_dir}/pft_ping.py \
 		--sendif ${epair}a \
 		--to 192.0.2.2 \
 		--replyif ${epair}a
 
 	# Change rules to now deny the ICMP traffic
 	pft_set_rules noflush alcatraz "block all"
 
 	# Established state means we can still ping alcatraz
 	atf_check -s exit:0 -o ignore ${common_dir}/pft_ping.py \
 		--sendif ${epair}a \
 		--to 192.0.2.2 \
 		--replyif ${epair}a
 
 	# Killing with the wrong IP doesn't affect our state
 	jexec alcatraz pfctl -k 192.0.2.3
 
 	# So we can still ping
 	atf_check -s exit:0 -o ignore ${common_dir}/pft_ping.py \
 		--sendif ${epair}a \
 		--to 192.0.2.2 \
 		--replyif ${epair}a
 
 	# Killing with one correct address and one incorrect doesn't kill the state
 	jexec alcatraz pfctl -k 192.0.2.1 -k 192.0.2.3
 
 	# So we can still ping
 	atf_check -s exit:0 -o ignore ${common_dir}/pft_ping.py \
 		--sendif ${epair}a \
 		--to 192.0.2.2 \
 		--replyif ${epair}a
 
 	# Killing with correct address does remove the state
 	jexec alcatraz pfctl -k 192.0.2.1
 
 	# Now the ping fails
 	atf_check -s exit:1 -o ignore ${common_dir}/pft_ping.py \
 		--sendif ${epair}a \
 		--to 192.0.2.2 \
 		--replyif ${epair}a
 }
 
 v4_cleanup()
 {
 	pft_cleanup
 }
 
 atf_test_case "v6" "cleanup"
 v6_head()
 {
 	atf_set descr 'Test killing states by IPv6 address'
 	atf_set require.user root
 	atf_set require.progs scapy
 }
 
 v6_body()
 {
 	pft_init
 
 	epair=$(vnet_mkepair)
 	ifconfig ${epair}a inet6 2001:db8::1/64 up no_dad
 
 	vnet_mkjail alcatraz ${epair}b
 	jexec alcatraz ifconfig ${epair}b inet6 2001:db8::2/64 up no_dad
 	jexec alcatraz pfctl -e
 
 	pft_set_rules alcatraz "block all" \
 		"pass in proto icmp6"
 
 	# Sanity check & establish state
 	# Note: use pft_ping so we always use the same ID, so pf considers all
 	# echo requests part of the same flow.
 	atf_check -s exit:0 -o ignore ${common_dir}/pft_ping.py \
 		--ip6 \
 		--sendif ${epair}a \
 		--to 2001:db8::2 \
 		--replyif ${epair}a
 
 	# Change rules to now deny the ICMP traffic
 	pft_set_rules noflush alcatraz "block all"
 
 	# Established state means we can still ping alcatraz
 	atf_check -s exit:0 -o ignore ${common_dir}/pft_ping.py \
 		--ip6 \
 		--sendif ${epair}a \
 		--to 2001:db8::2 \
 		--replyif ${epair}a
 
 	# Killing with the wrong IP doesn't affect our state
 	jexec alcatraz pfctl -k 2001:db8::3
 	atf_check -s exit:0 -o ignore ${common_dir}/pft_ping.py \
 		--ip6 \
 		--sendif ${epair}a \
 		--to 2001:db8::2 \
 		--replyif ${epair}a
 
 	# Killing with one correct address and one incorrect doesn't kill the state
 	jexec alcatraz pfctl -k 2001:db8::1 -k 2001:db8::3
 	atf_check -s exit:0 -o ignore ${common_dir}/pft_ping.py \
 		--ip6 \
 		--sendif ${epair}a \
 		--to 2001:db8::2 \
 		--replyif ${epair}a
 
 	# Killing with correct address does remove the state
 	jexec alcatraz pfctl -k 2001:db8::1
 	atf_check -s exit:1 -o ignore ${common_dir}/pft_ping.py \
 		--ip6 \
 		--sendif ${epair}a \
 		--to 2001:db8::2 \
 		--replyif ${epair}a
 
 }
 
 v6_cleanup()
 {
 	pft_cleanup
 }
 
 atf_test_case "label" "cleanup"
 label_head()
 {
 	atf_set descr 'Test killing states by label'
 	atf_set require.user root
 	atf_set require.progs scapy
 }
 
 label_body()
 {
 	pft_init
 
 	epair=$(vnet_mkepair)
 	ifconfig ${epair}a 192.0.2.1/24 up
 
 	vnet_mkjail alcatraz ${epair}b
 	jexec alcatraz ifconfig ${epair}b 192.0.2.2/24 up
 	jexec alcatraz pfctl -e
 
 	pft_set_rules alcatraz "block all" \
 		"pass in proto tcp label bar" \
 		"pass in proto icmp label foo"
 
 	# Sanity check & establish state
 	# Note: use pft_ping so we always use the same ID, so pf considers all
 	# echo requests part of the same flow.
 	atf_check -s exit:0 -o ignore ${common_dir}/pft_ping.py \
 		--sendif ${epair}a \
 		--to 192.0.2.2 \
 		--replyif ${epair}a
 
 	# Change rules to now deny the ICMP traffic
 	pft_set_rules noflush alcatraz "block all"
 
 	# Established state means we can still ping alcatraz
 	atf_check -s exit:0 -o ignore ${common_dir}/pft_ping.py \
 		--sendif ${epair}a \
 		--to 192.0.2.2 \
 		--replyif ${epair}a
 
 	# Killing a label on a different rules keeps the state
 	jexec alcatraz pfctl -k label -k bar
 	atf_check -s exit:0 -o ignore ${common_dir}/pft_ping.py \
 		--sendif ${epair}a \
 		--to 192.0.2.2 \
 		--replyif ${epair}a
 
 	# Killing a non-existing label keeps the state
 	jexec alcatraz pfctl -k label -k baz
 	atf_check -s exit:0 -o ignore ${common_dir}/pft_ping.py \
 		--sendif ${epair}a \
 		--to 192.0.2.2 \
 		--replyif ${epair}a
 
 	# Killing the correct label kills the state
 	jexec alcatraz pfctl -k label -k foo
 	atf_check -s exit:1 -o ignore ${common_dir}/pft_ping.py \
 		--sendif ${epair}a \
 		--to 192.0.2.2 \
 		--replyif ${epair}a
 }
 
 label_cleanup()
 {
 	pft_cleanup
 }
 
 atf_test_case "multilabel" "cleanup"
 multilabel_head()
 {
 	atf_set descr 'Test killing states with multiple labels by label'
 	atf_set require.user root
 	atf_set require.progs scapy
 }
 
 multilabel_body()
 {
 	pft_init
 
 	epair=$(vnet_mkepair)
 	ifconfig ${epair}a 192.0.2.1/24 up
 
 	vnet_mkjail alcatraz ${epair}b
 	jexec alcatraz ifconfig ${epair}b 192.0.2.2/24 up
 	jexec alcatraz pfctl -e
 
 	pft_set_rules alcatraz "block all" \
 		"pass in proto icmp label foo label bar"
 
 	# Sanity check & establish state
 	# Note: use pft_ping so we always use the same ID, so pf considers all
 	# echo requests part of the same flow.
 	atf_check -s exit:0 -o ignore ${common_dir}/pft_ping.py \
 		--sendif ${epair}a \
 		--to 192.0.2.2 \
 		--replyif ${epair}a
 
 	# Change rules to now deny the ICMP traffic
 	pft_set_rules noflush alcatraz "block all"
 
 	# Established state means we can still ping alcatraz
 	atf_check -s exit:0 -o ignore ${common_dir}/pft_ping.py \
 		--sendif ${epair}a \
 		--to 192.0.2.2 \
 		--replyif ${epair}a
 
 	# Killing a label on a different rules keeps the state
 	jexec alcatraz pfctl -k label -k baz
 	atf_check -s exit:0 -o ignore ${common_dir}/pft_ping.py \
 		--sendif ${epair}a \
 		--to 192.0.2.2 \
 		--replyif ${epair}a
 
 	# Killing the state with the last label works
 	jexec alcatraz pfctl -k label -k bar
 	atf_check -s exit:1 -o ignore ${common_dir}/pft_ping.py \
 		--sendif ${epair}a \
 		--to 192.0.2.2 \
 		--replyif ${epair}a
 
 	pft_set_rules alcatraz "block all" \
 		"pass in proto icmp label foo label bar"
 
 	# Reestablish state
 	atf_check -s exit:0 -o ignore ${common_dir}/pft_ping.py \
 		--sendif ${epair}a \
 		--to 192.0.2.2 \
 		--replyif ${epair}a
 
 	# Change rules to now deny the ICMP traffic
 	pft_set_rules noflush alcatraz "block all"
 
 	# Killing with the first label works too
 	jexec alcatraz pfctl -k label -k foo
 	atf_check -s exit:1 -o ignore ${common_dir}/pft_ping.py \
 		--sendif ${epair}a \
 		--to 192.0.2.2 \
 		--replyif ${epair}a
 }
 
 multilabel_cleanup()
 {
 	pft_cleanup
 }
 
 atf_test_case "gateway" "cleanup"
 gateway_head()
 {
 	atf_set descr 'Test killing states by route-to/reply-to address'
 	atf_set require.user root
 	atf_set require.progs scapy
 }
 
 gateway_body()
 {
 	pft_init
 
 	epair=$(vnet_mkepair)
 	ifconfig ${epair}a 192.0.2.1/24 up
 
 	vnet_mkjail alcatraz ${epair}b
 	jexec alcatraz ifconfig ${epair}b 192.0.2.2/24 up
 	jexec alcatraz pfctl -e
 
 	pft_set_rules alcatraz "block all" \
 		"pass in reply-to (${epair}b 192.0.2.1) proto icmp"
 
 	# Sanity check & establish state
 	# Note: use pft_ping so we always use the same ID, so pf considers all
 	# echo requests part of the same flow.
 	atf_check -s exit:0 -o ignore ${common_dir}/pft_ping.py \
 		--sendif ${epair}a \
 		--to 192.0.2.2 \
 		--replyif ${epair}a
 
 	# Change rules to now deny the ICMP traffic
 	pft_set_rules noflush alcatraz "block all"
 
 	# Established state means we can still ping alcatraz
 	atf_check -s exit:0 -o ignore ${common_dir}/pft_ping.py \
 		--sendif ${epair}a \
 		--to 192.0.2.2 \
 		--replyif ${epair}a
 
 	# Killing with a different gateway does not affect our state
 	jexec alcatraz pfctl -k gateway -k 192.0.2.2
 	atf_check -s exit:0 -o ignore ${common_dir}/pft_ping.py \
 		--sendif ${epair}a \
 		--to 192.0.2.2 \
 		--replyif ${epair}a
 
 	# Killing states with the relevant gateway does terminate our state
 	jexec alcatraz pfctl -k gateway -k 192.0.2.1
 	atf_check -s exit:1 -o ignore ${common_dir}/pft_ping.py \
 		--sendif ${epair}a \
 		--to 192.0.2.2 \
 		--replyif ${epair}a
 }
 
 gateway_cleanup()
 {
 	pft_cleanup
 }
 
 atf_test_case "match" "cleanup"
 match_head()
 {
 	atf_set descr 'Test killing matching states'
 	atf_set require.user root
 }
 
 match_body()
 {
 	pft_init
 
 	epair_one=$(vnet_mkepair)
 	ifconfig ${epair_one}a 192.0.2.1/24 up
 
 	epair_two=$(vnet_mkepair)
 
 	vnet_mkjail alcatraz ${epair_one}b ${epair_two}a
 	jexec alcatraz ifconfig ${epair_one}b 192.0.2.2/24 up
 	jexec alcatraz ifconfig ${epair_two}a 198.51.100.1/24 up
 	jexec alcatraz sysctl net.inet.ip.forwarding=1
 	jexec alcatraz pfctl -e
 
 	vnet_mkjail singsing ${epair_two}b
 	jexec singsing ifconfig ${epair_two}b 198.51.100.2/24 up
 	jexec singsing route add default 198.51.100.1
 	jexec singsing /usr/sbin/inetd -p inetd-echo.pid \
 	    $(atf_get_srcdir)/echo_inetd.conf
 
 	route add 198.51.100.0/24 192.0.2.2
 
 	pft_set_rules alcatraz \
 		"nat on ${epair_two}a from 192.0.2.0/24 -> (${epair_two}a)" \
 		"pass all"
 
 	nc 198.51.100.2 7 &
 
 	# Expect two states
 	states=$(jexec alcatraz pfctl -s s | wc -l)
 	if [ $states -ne 2 ] ;
 	then
 		atf_fail "Expected two states, found $states"
 	fi
 
 	# If we don't kill the matching NAT state one should be left
 	jexec alcatraz pfctl -k 192.0.2.1
 	states=$(jexec alcatraz pfctl -s s | wc -l)
 	if [ $states -ne 1 ] ;
 	then
 		atf_fail "Expected one states, found $states"
 	fi
 
 	# Flush
 	jexec alcatraz pfctl -F states
 
 	nc 198.51.100.2 7 &
 
 	# Kill matching states, expect all of them to be gone
 	jexec alcatraz pfctl -M -k 192.0.2.1
 	states=$(jexec alcatraz pfctl -s s | wc -l)
 	if [ $states -ne 0 ] ;
 	then
 		atf_fail "Expected zero states, found $states"
 	fi
 }
 
 match_cleanup()
 {
 	pft_cleanup
 }
 
+atf_test_case "interface" "cleanup"
+interface_head()
+{
+	atf_set descr 'Test killing states based on interface'
+	atf_set require.user root
+	atf_set require.progs scapy
+}
+
+interface_body()
+{
+	pft_init
+
+	epair=$(vnet_mkepair)
+	ifconfig ${epair}a 192.0.2.1/24 up
+
+	vnet_mkjail alcatraz ${epair}b
+	jexec alcatraz ifconfig ${epair}b 192.0.2.2/24 up
+	jexec alcatraz pfctl -e
+
+	pft_set_rules alcatraz "block all" \
+		"pass in proto icmp"
+
+	# Sanity check & establish state
+	# Note: use pft_ping so we always use the same ID, so pf considers all
+	# echo requests part of the same flow.
+	atf_check -s exit:0 -o ignore ${common_dir}/pft_ping.py \
+		--sendif ${epair}a \
+		--to 192.0.2.2 \
+		--replyif ${epair}a
+
+	# Change rules to now deny the ICMP traffic
+	pft_set_rules noflush alcatraz "block all"
+
+	# Established state means we can still ping alcatraz
+	atf_check -s exit:0 -o ignore ${common_dir}/pft_ping.py \
+		--sendif ${epair}a \
+		--to 192.0.2.2 \
+		--replyif ${epair}a
+
+	# Flushing states on a different interface doesn't affect our state
+	jexec alcatraz pfctl -i ${epair}a -Fs
+	atf_check -s exit:0 -o ignore ${common_dir}/pft_ping.py \
+		--sendif ${epair}a \
+		--to 192.0.2.2 \
+		--replyif ${epair}a
+
+	# Flushing on the correct interface does (even with floating states)
+	jexec alcatraz pfctl -i ${epair}b -Fs
+	atf_check -s exit:1 -o ignore ${common_dir}/pft_ping.py \
+		--sendif ${epair}a \
+		--to 192.0.2.2 \
+		--replyif ${epair}a
+}
+
+interface_cleanup()
+{
+	pft_cleanup
+}
+
 atf_init_test_cases()
 {
 	atf_add_test_case "v4"
 	atf_add_test_case "v6"
 	atf_add_test_case "label"
 	atf_add_test_case "multilabel"
 	atf_add_test_case "gateway"
 	atf_add_test_case "match"
+	atf_add_test_case "interface"
 }