diff --git a/distrib/sets/lists/tests/mi b/distrib/sets/lists/tests/mi
index 27f3a4abe14f..7767538508fb 100644
--- a/distrib/sets/lists/tests/mi
+++ b/distrib/sets/lists/tests/mi
@@ -1,4 +1,4 @@
-# $NetBSD: mi,v 1.694 2016/11/06 17:09:19 alnsn Exp $
+# $NetBSD: mi,v 1.695 2016/11/07 00:54:48 ozaki-r Exp $
 #
 # Note: don't delete entries from here - mark them as "obsolete" instead.
 #
@@ -3249,6 +3249,7 @@
 ./usr/tests/net/net/t_ipv6address		tests-net-tests		atf,rump
 ./usr/tests/net/net/t_ipv6_lifetime		tests-net-tests		atf,rump
 ./usr/tests/net/net/t_mtudisc			tests-net-tests		atf,rump
+./usr/tests/net/net/t_mtudisc6			tests-net-tests		atf,rump
 ./usr/tests/net/net/t_ping6_opts		tests-net-tests		atf,rump
 ./usr/tests/net/net/t_pktinfo			tests-net-tests		compattestfile,atf
 ./usr/tests/net/net/t_raw			tests-net-tests		atf,rump
diff --git a/tests/net/net/Makefile b/tests/net/net/Makefile
index d28f93b9902c..7b72fe93e66d 100644
--- a/tests/net/net/Makefile
+++ b/tests/net/net/Makefile
@@ -1,4 +1,4 @@
-# $NetBSD: Makefile,v 1.17 2016/10/31 10:38:25 ozaki-r Exp $
+# $NetBSD: Makefile,v 1.18 2016/11/07 00:54:48 ozaki-r Exp $
 #
 
 .include <bsd.own.mk>
@@ -16,6 +16,7 @@ TESTS_SH+=	t_ipaddress
 TESTS_SH+=	t_ipv6address
 TESTS_SH+=	t_ipv6_lifetime
 TESTS_SH+=	t_mtudisc
+TESTS_SH+=	t_mtudisc6
 TESTS_SH+=	t_ping6_opts
 .endif
 
diff --git a/tests/net/net/t_mtudisc6.sh b/tests/net/net/t_mtudisc6.sh
new file mode 100644
index 000000000000..683084b47f0b
--- /dev/null
+++ b/tests/net/net/t_mtudisc6.sh
@@ -0,0 +1,232 @@
+#	$NetBSD: t_mtudisc6.sh,v 1.1 2016/11/07 00:54:48 ozaki-r Exp $
+#
+# Copyright (c) 2016 Internet Initiative Japan Inc.
+# All rights reserved.
+#
+# 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
+#
+
+inetserver="rump_server -lrumpnet -lrumpnet_net -lrumpnet_netinet"
+inetserver="$inetserver -lrumpnet_netinet6 -lrumpnet_shmif"
+inetserver="$inetserver -lrumpdev"
+HIJACKING="env LD_PRELOAD=/usr/lib/librumphijack.so RUMPHIJACK=sysctl=yes"
+
+SOCKLOCAL=unix://commsock1
+SOCKGATEWAY=unix://commsock2
+SOCKREMOTE=unix://commsock3
+HTTPD_PID=httpd.pid
+HTML_FILE=index.html
+
+DEBUG=${DEBUG:-false}
+
+atf_test_case mtudisc6_basic cleanup
+
+mtudisc6_basic_head()
+{
+
+	atf_set "descr" "Tests for IPv6 Path MTU Dicorvery basic behavior"
+	atf_set "require.progs" "rump_server"
+}
+
+setup_server()
+{
+	local sock=$1
+	local if=$2
+	local bus=$3
+	local ip=$4
+
+	export RUMP_SERVER=$sock
+
+	atf_check -s exit:0 rump.ifconfig $if create
+	atf_check -s exit:0 rump.ifconfig $if linkstr $bus
+	atf_check -s exit:0 rump.ifconfig $if inet6 $ip
+	atf_check -s exit:0 rump.ifconfig $if up
+	atf_check -s exit:0 rump.ifconfig -w 10
+
+	$DEBUG && rump.ifconfig $if
+}
+
+extract_new_packets()
+{
+	local bus=$1
+	local old=./old
+
+	if [ ! -f $old ]; then
+		old=/dev/null
+	fi
+
+	shmif_dumpbus -p - $bus 2>/dev/null| \
+	    tcpdump -n -e -r - 2>/dev/null > ./new
+	diff -u $old ./new |grep '^+' |cut -d '+' -f 2 > ./diff
+	mv -f ./new ./old
+	cat ./diff
+}
+
+setup_httpd()
+{
+	local sock=$1
+	local ip=$2
+	local data="0123456789"
+
+	export RUMP_SERVER=$sock
+
+	touch $HTML_FILE
+	for i in `seq 1 512`
+	do
+		echo $data >> $HTML_FILE
+	done
+
+	# start httpd in daemon mode
+	atf_check -s exit:0 env LD_PRELOAD=/usr/lib/librumphijack.so \
+	    /usr/libexec/httpd -P $HTTPD_PID -i $ip -b -s $(pwd)
+
+	$DEBUG && rump.netstat -a
+
+	sleep 5
+}
+
+do_http_get()
+{
+	local ip=$1
+	local ret=$2
+	local timeout=5
+
+	# get the webpage
+	atf_check -s exit:$ret env LD_PRELOAD=/usr/lib/librumphijack.so	\
+	    ftp -q $timeout -o ./out "http://[$ip]/$HTML_FILE"
+}
+
+mtudisc6_basic_body()
+{
+	local pkt=
+	local local_ip=fc00:0:0:1::2
+	local gateway_local_ip=fc00:0:0:1::1
+	local gateway_remote_ip=fc00:0:0:2::1
+	local remote_ip=fc00:0:0:2::2
+	local prefixlen=64
+
+	atf_check -s exit:0 ${inetserver} $SOCKLOCAL
+	atf_check -s exit:0 ${inetserver} $SOCKGATEWAY
+	atf_check -s exit:0 ${inetserver} $SOCKREMOTE
+
+	#
+	# Setup servers
+	#
+	# [local server]       [gateway server]      [remote server]
+	#       |                 |        |                |
+	# shmif0(1500) -- shmif1(1280)  shmif0(1500) -- shmif0(1500)
+	#
+
+	# Assign IP addresses
+	setup_server $SOCKLOCAL shmif0 bus1 $local_ip/$prefixlen
+	setup_server $SOCKGATEWAY shmif0 bus1 $gateway_local_ip/$prefixlen
+	setup_server $SOCKGATEWAY shmif1 bus2 $gateway_remote_ip/$prefixlen
+	setup_server $SOCKREMOTE shmif0 bus2 $remote_ip/$prefixlen
+
+	### Setup gateway server
+	export RUMP_SERVER=$SOCKGATEWAY
+
+	# Set MTU of shmif0 to 1280
+	export RUMP_SERVER=$SOCKGATEWAY
+	atf_check -s exit:0 rump.ifconfig shmif0 mtu 1280
+
+	# Enable IPv6 forwarding
+	atf_check -s exit:0 rump.sysctl -w -q net.inet6.ip6.forwarding=1
+
+	### Setup remote server
+	export RUMP_SERVER=$SOCKREMOTE
+
+	# Start httpd daemon
+	setup_httpd $SOCKREMOTE $remote_ip
+
+	# Teach the peer that local serer is behind gateway server
+	atf_check -s exit:0 -o ignore \
+	    rump.route add -inet6 $local_ip/128 $gateway_remote_ip
+
+	# Check path MTU size on remote server
+	atf_check -s exit:0 \
+	    -o match:"^$local_ip +$gateway_remote_ip +UGHS +- +- +- +shmif0" \
+	    rump.netstat -nr -f inet6
+
+	### Setup local server
+	export RUMP_SERVER=$SOCKLOCAL
+
+	# Teach the peer that remote serer is behind gateway server
+	atf_check -s exit:0 -o ignore \
+	    rump.route add -inet6 $remote_ip/128 $gateway_local_ip
+
+	# Don't accept fragmented packets
+	atf_check -s exit:0 -o ignore \
+	    rump.sysctl -w -q net.inet6.ip6.maxfragpackets=0
+
+	#
+	# Test enabled path MTU discorvery
+	#
+	# Get the webpage (expect: success)
+	export RUMP_SERVER=$SOCKLOCAL
+	do_http_get $remote_ip 0
+	$DEBUG && extract_new_packets bus2 > ./out
+	$DEBUG && cat ./out
+
+	# Check path MTU size on remote server
+	export RUMP_SERVER=$SOCKREMOTE
+	atf_check -s exit:0 \
+	    -o match:"^$local_ip +$gateway_remote_ip +UGHS +- +- +1280 +shmif0" \
+	    rump.netstat -nr -f inet6
+}
+
+dump_server()
+{
+	local sock=$1
+
+	export RUMP_SERVER=$sock
+	rump.netstat -nr -f inet6
+	rump.ndp -n -a
+	rump.ifconfig
+	$HIJACKING dmesg
+}
+
+dump()
+{
+
+	dump_server $SOCKLOCAL
+	dump_server $SOCKGATEWAY
+	dump_server $SOCKREMOTE
+	shmif_dumpbus -p - bus1 2>/dev/null| tcpdump -n -e -r -
+	shmif_dumpbus -p - bus2 2>/dev/null| tcpdump -n -e -r -
+}
+
+mtudisc6_basic_cleanup()
+{
+
+	$DEBUG && dump
+	kill "$(cat ${HTTPD_PID})"
+	env RUMP_SERVER=$SOCKLOCAL rump.halt
+	env RUMP_SERVER=$SOCKGATEWAY rump.halt
+	env RUMP_SERVER=$SOCKREMOTE rump.halt
+}
+
+atf_init_test_cases()
+{
+
+	atf_add_test_case mtudisc6_basic
+}