diff --git a/smoketest/scripts/cli/base_interfaces_test.py b/smoketest/scripts/cli/base_interfaces_test.py
index 59a9c85c0..44f99ffab 100644
--- a/smoketest/scripts/cli/base_interfaces_test.py
+++ b/smoketest/scripts/cli/base_interfaces_test.py
@@ -1,733 +1,777 @@
 # Copyright (C) 2019-2021 VyOS maintainers and contributors
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 or later as
 # published by the Free Software Foundation.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import os
 import unittest
 
 from binascii import hexlify
 
 from netifaces import AF_INET
 from netifaces import AF_INET6
 from netifaces import ifaddresses
 from netifaces import interfaces
 
 from base_vyostest_shim import VyOSUnitTestSHIM
 
 from vyos.configsession import ConfigSession
+from vyos.configsession import ConfigSessionError
 from vyos.ifconfig import Interface
 from vyos.ifconfig import Section
 from vyos.util import read_file
 from vyos.util import cmd
 from vyos.util import dict_search
 from vyos.util import process_named_running
 from vyos.util import get_interface_config
 from vyos.validate import is_intf_addr_assigned
 from vyos.validate import is_ipv6_link_local
 
 def is_mirrored_to(interface, mirror_if, qdisc):
     """
     Ask TC if we are mirroring traffic to a discrete interface.
 
     interface: source interface
     mirror_if: destination where we mirror our data to
     qdisc: must be ffff or 1 for ingress/egress
     """
     if qdisc not in ['ffff', '1']:
         raise ValueError()
 
     ret_val = False
     tmp = cmd(f'tc -s -p filter ls dev {interface} parent {qdisc}: | grep mirred')
     tmp = tmp.lower()
     if mirror_if in tmp:
         ret_val = True
     return ret_val
 
 class BasicInterfaceTest:
     class TestCase(VyOSUnitTestSHIM.TestCase):
         _test_ip = False
         _test_mtu = False
         _test_vlan = False
         _test_qinq = False
         _test_ipv6 = False
         _test_ipv6_pd = False
         _test_ipv6_dhcpc6 = False
         _test_mirror = False
         _base_path = []
 
         _options = {}
         _interfaces = []
         _qinq_range = ['10', '20', '30']
         _vlan_range = ['100', '200', '300', '2000']
         _test_addr = ['192.0.2.1/26', '192.0.2.255/31', '192.0.2.64/32',
                       '2001:db8:1::ffff/64', '2001:db8:101::1/112']
 
         _mirror_interfaces = []
         # choose IPv6 minimum MTU value for tests - this must always work
         _mtu = '1280'
 
         def setUp(self):
             # Setup mirror interfaces for SPAN (Switch Port Analyzer)
             for span in self._mirror_interfaces:
                 section = Section.section(span)
                 self.cli_set(['interfaces', section, span])
 
         def tearDown(self):
             # Tear down mirror interfaces for SPAN (Switch Port Analyzer)
             for span in self._mirror_interfaces:
                 section = Section.section(span)
                 self.cli_delete(['interfaces', section, span])
 
             self.cli_delete(self._base_path)
             self.cli_commit()
 
             # Verify that no previously interface remained on the system
             for intf in self._interfaces:
                 self.assertNotIn(intf, interfaces())
 
         def test_span_mirror(self):
             if not self._mirror_interfaces:
                 self.skipTest('not supported')
 
             # Check the two-way mirror rules of ingress and egress
             for mirror in self._mirror_interfaces:
                 for interface in self._interfaces:
                     self.cli_set(self._base_path + [interface, 'mirror', 'ingress', mirror])
                     self.cli_set(self._base_path + [interface, 'mirror', 'egress',  mirror])
 
             self.cli_commit()
 
             # Verify config
             for mirror in self._mirror_interfaces:
                 for interface in self._interfaces:
                     self.assertTrue(is_mirrored_to(interface, mirror, 'ffff'))
                     self.assertTrue(is_mirrored_to(interface, mirror, '1'))
 
         def test_interface_disable(self):
             # Check if description can be added to interface and
             # can be read back
             for intf in self._interfaces:
                 self.cli_set(self._base_path + [intf, 'disable'])
                 for option in self._options.get(intf, []):
                     self.cli_set(self._base_path + [intf] + option.split())
 
             self.cli_commit()
 
             # Validate interface description
             for intf in self._interfaces:
                 self.assertEqual(Interface(intf).get_admin_state(), 'down')
 
         def test_interface_description(self):
             # Check if description can be added to interface and
             # can be read back
             for intf in self._interfaces:
                 test_string=f'Description-Test-{intf}'
                 self.cli_set(self._base_path + [intf, 'description', test_string])
                 for option in self._options.get(intf, []):
                     self.cli_set(self._base_path + [intf] + option.split())
 
             self.cli_commit()
 
             # Validate interface description
             for intf in self._interfaces:
                 test_string=f'Description-Test-{intf}'
                 tmp = read_file(f'/sys/class/net/{intf}/ifalias')
                 self.assertEqual(tmp, test_string)
                 self.assertEqual(Interface(intf).get_alias(), test_string)
                 self.cli_delete(self._base_path + [intf, 'description'])
 
             self.cli_commit()
 
             # Validate remove interface description "empty"
             for intf in self._interfaces:
                 tmp = read_file(f'/sys/class/net/{intf}/ifalias')
                 self.assertEqual(tmp, str())
                 self.assertEqual(Interface(intf).get_alias(), str())
 
         def test_add_single_ip_address(self):
             addr = '192.0.2.0/31'
             for intf in self._interfaces:
                 self.cli_set(self._base_path + [intf, 'address', addr])
                 for option in self._options.get(intf, []):
                     self.cli_set(self._base_path + [intf] + option.split())
 
             self.cli_commit()
 
             for intf in self._interfaces:
                 self.assertTrue(is_intf_addr_assigned(intf, addr))
                 self.assertEqual(Interface(intf).get_admin_state(), 'up')
 
         def test_add_multiple_ip_addresses(self):
             # Add address
             for intf in self._interfaces:
                 for addr in self._test_addr:
                     self.cli_set(self._base_path + [intf, 'address', addr])
                     for option in self._options.get(intf, []):
                         self.cli_set(self._base_path + [intf] + option.split())
 
             self.cli_commit()
 
             # Validate address
             for intf in self._interfaces:
                 for af in AF_INET, AF_INET6:
                     for addr in ifaddresses(intf)[af]:
                         # checking link local addresses makes no sense
                         if is_ipv6_link_local(addr['addr']):
                             continue
 
                         self.assertTrue(is_intf_addr_assigned(intf, addr['addr']))
 
         def test_ipv6_link_local_address(self):
             # Common function for IPv6 link-local address assignemnts
             if not self._test_ipv6:
                 self.skipTest('not supported')
 
             for interface in self._interfaces:
                 base = self._base_path + [interface]
                 for option in self._options.get(interface, []):
                     self.cli_set(base + option.split())
 
             # after commit we must have an IPv6 link-local address
             self.cli_commit()
 
             for interface in self._interfaces:
                 for addr in ifaddresses(interface)[AF_INET6]:
                     self.assertTrue(is_ipv6_link_local(addr['addr']))
 
             # disable IPv6 link-local address assignment
             for interface in self._interfaces:
                 base = self._base_path + [interface]
                 self.cli_set(base + ['ipv6', 'address', 'no-default-link-local'])
 
             # after commit we must have no IPv6 link-local address
             self.cli_commit()
 
             for interface in self._interfaces:
                 self.assertTrue(AF_INET6 not in ifaddresses(interface))
 
         def test_interface_mtu(self):
             if not self._test_mtu:
                 self.skipTest('not supported')
 
             for intf in self._interfaces:
                 base = self._base_path + [intf]
                 self.cli_set(base + ['mtu', self._mtu])
                 for option in self._options.get(intf, []):
                     self.cli_set(base + option.split())
 
             # commit interface changes
             self.cli_commit()
 
             # verify changed MTU
             for intf in self._interfaces:
                 tmp = get_interface_config(intf)
                 self.assertEqual(tmp['mtu'], int(self._mtu))
 
         def test_mtu_1200_no_ipv6_interface(self):
             # Testcase if MTU can be changed to 1200 on non IPv6
             # enabled interfaces
             if not self._test_mtu:
                 self.skipTest('not supported')
 
             old_mtu = self._mtu
             self._mtu = '1200'
 
             for intf in self._interfaces:
                 base = self._base_path + [intf]
                 self.cli_set(base + ['mtu', self._mtu])
                 self.cli_set(base + ['ipv6', 'address', 'no-default-link-local'])
 
                 for option in self._options.get(intf, []):
                     self.cli_set(base + option.split())
 
             # commit interface changes
             self.cli_commit()
 
             # verify changed MTU
             for intf in self._interfaces:
                 tmp = get_interface_config(intf)
                 self.assertEqual(tmp['mtu'], int(self._mtu))
 
             self._mtu = old_mtu
 
         def test_vif_8021q_interfaces(self):
             # XXX: This testcase is not allowed to run as first testcase, reason
             # is the Wireless test will first load the wifi kernel hwsim module
             # which creates a wlan0 and wlan1 interface which will fail the
             # tearDown() test in the end that no interface is allowed to survive!
             if not self._test_vlan:
                 self.skipTest('not supported')
 
             for interface in self._interfaces:
                 base = self._base_path + [interface]
                 for option in self._options.get(interface, []):
                     self.cli_set(base + option.split())
 
                 for vlan in self._vlan_range:
                     base = self._base_path + [interface, 'vif', vlan]
                     for address in self._test_addr:
                         self.cli_set(base + ['address', address])
                     self.cli_set(base + ['ingress-qos', '0:1'])
                     self.cli_set(base + ['egress-qos', '1:6'])
 
             self.cli_commit()
 
             for intf in self._interfaces:
                 for vlan in self._vlan_range:
                     vif = f'{intf}.{vlan}'
                     tmp = get_interface_config(f'{vif}')
 
                     tmp2 = dict_search('linkinfo.info_data.ingress_qos', tmp)
                     for item in tmp2 if tmp2 else []:
                         from_key = item['from']
                         to_key = item['to']
                         self.assertEqual(from_key, 0)
                         self.assertEqual(to_key, 1)
 
                     tmp2 = dict_search('linkinfo.info_data.egress_qos', tmp)
                     for item in tmp2 if tmp2 else []:
                         from_key = item['from']
                         to_key = item['to']
                         self.assertEqual(from_key, 1)
                         self.assertEqual(to_key, 6)
 
                     for address in self._test_addr:
                         self.assertTrue(is_intf_addr_assigned(vif, address))
 
                     self.assertEqual(Interface(vif).get_admin_state(), 'up')
-        
+
+        def test_vif_8021q_mtu_limits(self):
+            # XXX: This testcase is not allowed to run as first testcase, reason
+            # is the Wireless test will first load the wifi kernel hwsim module
+            # which creates a wlan0 and wlan1 interface which will fail the
+            # tearDown() test in the end that no interface is allowed to survive!
+            if not self._test_vlan:
+                self.skipTest('not supported')
+
+            mtu_1500 = '1500'
+            mtu_9000 = '9000'
+
+            for interface in self._interfaces:
+                base = self._base_path + [interface]
+                self.cli_set(base + ['mtu', mtu_1500])
+                for option in self._options.get(interface, []):
+                    self.cli_set(base + option.split())
+
+                for vlan in self._vlan_range:
+                    base = self._base_path + [interface, 'vif', vlan]
+                    self.cli_set(base + ['mtu', mtu_9000])
+
+            # check validate() - VIF MTU must not be larger the parent interface
+            # MTU size.
+            with self.assertRaises(ConfigSessionError):
+                self.cli_commit()
+
+            # Change MTU on base interface to be the same as on the VIF interface
+            for interface in self._interfaces:
+                base = self._base_path + [interface]
+                self.cli_set(base + ['mtu', mtu_9000])
+
+            self.cli_commit()
+
+            # Verify MTU on base and VIF interfaces
+            for interface in self._interfaces:
+                tmp = get_interface_config(interface)
+                self.assertEqual(tmp['mtu'], int(mtu_9000))
+
+                for vlan in self._vlan_range:
+                    tmp = get_interface_config(f'{interface}.{vlan}')
+                    self.assertEqual(tmp['mtu'], int(mtu_9000))
+
+
         def test_vif_qos_change(self):
             # XXX: This testcase is not allowed to run as first testcase, reason
             # is the Wireless test will first load the wifi kernel hwsim module
             # which creates a wlan0 and wlan1 interface which will fail the
             # tearDown() test in the end that no interface is allowed to survive!
             if not self._test_vlan:
                 self.skipTest('not supported')
 
             for interface in self._interfaces:
                 base = self._base_path + [interface]
                 for option in self._options.get(interface, []):
                     self.cli_set(base + option.split())
 
                 for vlan in self._vlan_range:
                     base = self._base_path + [interface, 'vif', vlan]
                     for address in self._test_addr:
                         self.cli_set(base + ['address', address])
                     self.cli_set(base + ['ingress-qos', '0:1'])
                     self.cli_set(base + ['egress-qos', '1:6'])
 
             self.cli_commit()
 
             for intf in self._interfaces:
                 for vlan in self._vlan_range:
                     vif = f'{intf}.{vlan}'
                     tmp = get_interface_config(f'{vif}')
 
                     tmp2 = dict_search('linkinfo.info_data.ingress_qos', tmp)
                     for item in tmp2 if tmp2 else []:
                         from_key = item['from']
                         to_key = item['to']
                         self.assertEqual(from_key, 0)
                         self.assertEqual(to_key, 1)
 
                     tmp2 = dict_search('linkinfo.info_data.egress_qos', tmp)
                     for item in tmp2 if tmp2 else []:
                         from_key = item['from']
                         to_key = item['to']
                         self.assertEqual(from_key, 1)
                         self.assertEqual(to_key, 6)
 
                     for address in self._test_addr:
                         self.assertTrue(is_intf_addr_assigned(vif, address))
 
                     self.assertEqual(Interface(vif).get_admin_state(), 'up')
 
             new_ingress_qos_from = 1
             new_ingress_qos_to = 6
             new_egress_qos_from = 2
             new_egress_qos_to = 7
             for interface in self._interfaces:
                 base = self._base_path + [interface]
                 for vlan in self._vlan_range:
                     base = self._base_path + [interface, 'vif', vlan]
                     self.cli_delete(base + ['ingress-qos', '0:1'])
                     self.cli_delete(base + ['egress-qos', '1:6'])
                     self.cli_set(base + ['ingress-qos', f'{new_ingress_qos_from}:{new_ingress_qos_to}'])
                     self.cli_set(base + ['egress-qos', f'{new_egress_qos_from}:{new_egress_qos_to}'])
 
             self.cli_commit()
 
             for intf in self._interfaces:
                 for vlan in self._vlan_range:
                     vif = f'{intf}.{vlan}'
                     tmp = get_interface_config(f'{vif}')
 
                     tmp2 = dict_search('linkinfo.info_data.ingress_qos', tmp)
                     if tmp2:
                         from_key = tmp2[0]['from']
                         to_key = tmp2[0]['to']
                         self.assertEqual(from_key, new_ingress_qos_from)
                         self.assertEqual(to_key, new_ingress_qos_to)
 
                     tmp2 = dict_search('linkinfo.info_data.egress_qos', tmp)
                     if tmp2:
                         from_key = tmp2[0]['from']
                         to_key = tmp2[0]['to']
                         self.assertEqual(from_key, new_egress_qos_from)
                         self.assertEqual(to_key, new_egress_qos_to)
 
         def test_vif_8021q_lower_up_down(self):
             # Testcase for https://phabricator.vyos.net/T3349
             if not self._test_vlan:
                 self.skipTest('not supported')
 
             for interface in self._interfaces:
                 base = self._base_path + [interface]
                 for option in self._options.get(interface, []):
                     self.cli_set(base + option.split())
 
                 # disable the lower interface
                 self.cli_set(base + ['disable'])
 
                 for vlan in self._vlan_range:
                     vlan_base = self._base_path + [interface, 'vif', vlan]
                     # disable the vlan interface
                     self.cli_set(vlan_base + ['disable'])
 
             self.cli_commit()
 
             # re-enable all lower interfaces
             for interface in self._interfaces:
                 base = self._base_path + [interface]
                 self.cli_delete(base + ['disable'])
 
             self.cli_commit()
 
             # verify that the lower interfaces are admin up and the vlan
             # interfaces are all admin down
             for interface in self._interfaces:
                 self.assertEqual(Interface(interface).get_admin_state(), 'up')
 
                 for vlan in self._vlan_range:
                     ifname = f'{interface}.{vlan}'
                     self.assertEqual(Interface(ifname).get_admin_state(), 'down')
 
 
         def test_vif_s_8021ad_vlan_interfaces(self):
             # XXX: This testcase is not allowed to run as first testcase, reason
             # is the Wireless test will first load the wifi kernel hwsim module
             # which creates a wlan0 and wlan1 interface which will fail the
             # tearDown() test in the end that no interface is allowed to survive!
             if not self._test_qinq:
                 self.skipTest('not supported')
 
             for interface in self._interfaces:
                 base = self._base_path + [interface]
                 for option in self._options.get(interface, []):
                     self.cli_set(base + option.split())
 
                 for vif_s in self._qinq_range:
                     for vif_c in self._vlan_range:
                         base = self._base_path + [interface, 'vif-s', vif_s, 'vif-c', vif_c]
                         self.cli_set(base + ['mtu', self._mtu])
                         for address in self._test_addr:
                             self.cli_set(base + ['address', address])
 
             self.cli_commit()
 
             for interface in self._interfaces:
                 for vif_s in self._qinq_range:
                     tmp = get_interface_config(f'{interface}.{vif_s}')
                     self.assertEqual(dict_search('linkinfo.info_data.protocol', tmp), '802.1ad')
 
                     for vif_c in self._vlan_range:
                         vif = f'{interface}.{vif_s}.{vif_c}'
                         # For an unknown reason this regularely fails on the QEMU builds,
                         # thus the test for reading back IP addresses is temporary
                         # disabled. There is no big deal here, as this uses the same
                         # methods on 802.1q and here it works and is verified.
 #                       for address in self._test_addr:
 #                           self.assertTrue(is_intf_addr_assigned(vif, address))
 
                         tmp = get_interface_config(vif)
                         self.assertEqual(tmp['mtu'], int(self._mtu))
 
         def test_vif_s_protocol_change(self):
             # XXX: This testcase is not allowed to run as first testcase, reason
             # is the Wireless test will first load the wifi kernel hwsim module
             # which creates a wlan0 and wlan1 interface which will fail the
             # tearDown() test in the end that no interface is allowed to survive!
             if not self._test_qinq:
                 self.skipTest('not supported')
 
             for interface in self._interfaces:
                 base = self._base_path + [interface]
                 for option in self._options.get(interface, []):
                     self.cli_set(base + option.split())
 
                 for vif_s in self._qinq_range:
                     for vif_c in self._vlan_range:
                         base = self._base_path + [interface, 'vif-s', vif_s, 'vif-c', vif_c]
                         for address in self._test_addr:
                             self.cli_set(base + ['address', address])
 
             self.cli_commit()
 
             for interface in self._interfaces:
                 for vif_s in self._qinq_range:
                     tmp = get_interface_config(f'{interface}.{vif_s}')
                     # check for the default value
                     self.assertEqual(tmp['linkinfo']['info_data']['protocol'], '802.1ad')
 
             # T3532: now change ethertype
             new_protocol = '802.1q'
             for interface in self._interfaces:
                 for vif_s in self._qinq_range:
                     base = self._base_path + [interface, 'vif-s', vif_s]
                     self.cli_set(base + ['protocol', new_protocol])
 
             self.cli_commit()
 
             # Verify new ethertype configuration
             for interface in self._interfaces:
                 for vif_s in self._qinq_range:
                     tmp = get_interface_config(f'{interface}.{vif_s}')
                     self.assertEqual(tmp['linkinfo']['info_data']['protocol'], new_protocol.upper())
 
         def test_interface_ip_options(self):
             if not self._test_ip:
                 self.skipTest('not supported')
 
             for interface in self._interfaces:
                 arp_tmo = '300'
                 path = self._base_path + [interface]
                 for option in self._options.get(interface, []):
                     self.cli_set(path + option.split())
 
                 # Options
                 self.cli_set(path + ['ip', 'arp-cache-timeout', arp_tmo])
                 self.cli_set(path + ['ip', 'disable-arp-filter'])
                 self.cli_set(path + ['ip', 'disable-forwarding'])
                 self.cli_set(path + ['ip', 'enable-arp-accept'])
                 self.cli_set(path + ['ip', 'enable-arp-announce'])
                 self.cli_set(path + ['ip', 'enable-arp-ignore'])
                 self.cli_set(path + ['ip', 'enable-proxy-arp'])
                 self.cli_set(path + ['ip', 'proxy-arp-pvlan'])
                 self.cli_set(path + ['ip', 'source-validation', 'loose'])
 
             self.cli_commit()
 
             for interface in self._interfaces:
                 tmp = read_file(f'/proc/sys/net/ipv4/neigh/{interface}/base_reachable_time_ms')
                 self.assertEqual(tmp, str((int(arp_tmo) * 1000))) # tmo value is in milli seconds
 
                 tmp = read_file(f'/proc/sys/net/ipv4/conf/{interface}/arp_filter')
                 self.assertEqual('0', tmp)
 
                 tmp = read_file(f'/proc/sys/net/ipv4/conf/{interface}/arp_accept')
                 self.assertEqual('1', tmp)
 
                 tmp = read_file(f'/proc/sys/net/ipv4/conf/{interface}/arp_announce')
                 self.assertEqual('1', tmp)
 
                 tmp = read_file(f'/proc/sys/net/ipv4/conf/{interface}/arp_ignore')
                 self.assertEqual('1', tmp)
 
                 tmp = read_file(f'/proc/sys/net/ipv4/conf/{interface}/forwarding')
                 self.assertEqual('0', tmp)
 
                 tmp = read_file(f'/proc/sys/net/ipv4/conf/{interface}/proxy_arp')
                 self.assertEqual('1', tmp)
 
                 tmp = read_file(f'/proc/sys/net/ipv4/conf/{interface}/proxy_arp_pvlan')
                 self.assertEqual('1', tmp)
 
                 tmp = read_file(f'/proc/sys/net/ipv4/conf/{interface}/rp_filter')
                 self.assertEqual('2', tmp)
 
         def test_interface_ipv6_options(self):
             if not self._test_ipv6:
                 self.skipTest('not supported')
 
             for interface in self._interfaces:
                 dad_transmits = '10'
                 path = self._base_path + [interface]
                 for option in self._options.get(interface, []):
                     self.cli_set(path + option.split())
 
                 # Options
                 self.cli_set(path + ['ipv6', 'disable-forwarding'])
                 self.cli_set(path + ['ipv6', 'dup-addr-detect-transmits', dad_transmits])
 
             self.cli_commit()
 
             for interface in self._interfaces:
                 tmp = read_file(f'/proc/sys/net/ipv6/conf/{interface}/forwarding')
                 self.assertEqual('0', tmp)
 
                 tmp = read_file(f'/proc/sys/net/ipv6/conf/{interface}/dad_transmits')
                 self.assertEqual(dad_transmits, tmp)
 
         def test_dhcpv6_client_options(self):
             if not self._test_ipv6_dhcpc6:
                 self.skipTest('not supported')
 
             duid_base = 10
             for interface in self._interfaces:
                 duid = '00:01:00:01:27:71:db:f0:00:50:00:00:00:{}'.format(duid_base)
                 path = self._base_path + [interface]
                 for option in self._options.get(interface, []):
                     self.cli_set(path + option.split())
 
                 # Enable DHCPv6 client
                 self.cli_set(path + ['address', 'dhcpv6'])
                 self.cli_set(path + ['dhcpv6-options', 'rapid-commit'])
                 self.cli_set(path + ['dhcpv6-options', 'parameters-only'])
                 self.cli_set(path + ['dhcpv6-options', 'duid', duid])
                 duid_base += 1
 
             self.cli_commit()
 
             duid_base = 10
             for interface in self._interfaces:
                 duid = '00:01:00:01:27:71:db:f0:00:50:00:00:00:{}'.format(duid_base)
                 dhcpc6_config = read_file(f'/run/dhcp6c/dhcp6c.{interface}.conf')
                 self.assertIn(f'interface {interface} ' + '{', dhcpc6_config)
                 self.assertIn(f'  request domain-name-servers;', dhcpc6_config)
                 self.assertIn(f'  request domain-name;', dhcpc6_config)
                 self.assertIn(f'  information-only;', dhcpc6_config)
                 self.assertIn(f'  send ia-na 0;', dhcpc6_config)
                 self.assertIn(f'  send rapid-commit;', dhcpc6_config)
                 self.assertIn(f'  send client-id {duid};', dhcpc6_config)
                 self.assertIn('};', dhcpc6_config)
                 duid_base += 1
 
             # Check for running process
             self.assertTrue(process_named_running('dhcp6c'))
 
         def test_dhcpv6pd_auto_sla_id(self):
             if not self._test_ipv6_pd:
                 self.skipTest('not supported')
 
             prefix_len = '56'
             sla_len = str(64 - int(prefix_len))
 
             delegatees = ['dum2340', 'dum2341', 'dum2342', 'dum2343', 'dum2344']
 
             for interface in self._interfaces:
                 path = self._base_path + [interface]
                 for option in self._options.get(interface, []):
                     self.cli_set(path + option.split())
 
                 address = '1'
                 # prefix delegation stuff
                 pd_base = path + ['dhcpv6-options', 'pd', '0']
                 self.cli_set(pd_base + ['length', prefix_len])
 
                 for delegatee in delegatees:
                     section = Section.section(delegatee)
                     self.cli_set(['interfaces', section, delegatee])
                     self.cli_set(pd_base + ['interface', delegatee, 'address', address])
                     # increment interface address
                     address = str(int(address) + 1)
 
             self.cli_commit()
 
             for interface in self._interfaces:
                 dhcpc6_config = read_file(f'/run/dhcp6c/dhcp6c.{interface}.conf')
 
                 # verify DHCPv6 prefix delegation
                 self.assertIn(f'prefix ::/{prefix_len} infinity;', dhcpc6_config)
 
                 address = '1'
                 sla_id = '0'
                 for delegatee in delegatees:
                     self.assertIn(f'prefix-interface {delegatee}' + r' {', dhcpc6_config)
                     self.assertIn(f'ifid {address};', dhcpc6_config)
                     self.assertIn(f'sla-id {sla_id};', dhcpc6_config)
                     self.assertIn(f'sla-len {sla_len};', dhcpc6_config)
 
                     # increment sla-id
                     sla_id = str(int(sla_id) + 1)
                     # increment interface address
                     address = str(int(address) + 1)
 
             # Check for running process
             self.assertTrue(process_named_running('dhcp6c'))
 
             for delegatee in delegatees:
                 # we can already cleanup the test delegatee interface here
                 # as until commit() is called, nothing happens
                 section = Section.section(delegatee)
                 self.cli_delete(['interfaces', section, delegatee])
 
         def test_dhcpv6pd_manual_sla_id(self):
             if not self._test_ipv6_pd:
                 self.skipTest('not supported')
 
             prefix_len = '56'
             sla_len = str(64 - int(prefix_len))
 
             delegatees = ['dum3340', 'dum3341', 'dum3342', 'dum3343', 'dum3344']
 
             for interface in self._interfaces:
                 path = self._base_path + [interface]
                 for option in self._options.get(interface, []):
                     self.cli_set(path + option.split())
 
                 # prefix delegation stuff
                 address = '1'
                 sla_id = '1'
                 pd_base = path + ['dhcpv6-options', 'pd', '0']
                 self.cli_set(pd_base + ['length', prefix_len])
 
                 for delegatee in delegatees:
                     section = Section.section(delegatee)
                     self.cli_set(['interfaces', section, delegatee])
                     self.cli_set(pd_base + ['interface', delegatee, 'address', address])
                     self.cli_set(pd_base + ['interface', delegatee, 'sla-id', sla_id])
 
                     # increment interface address
                     address = str(int(address) + 1)
                     sla_id = str(int(sla_id) + 1)
 
             self.cli_commit()
 
             # Verify dhcpc6 client configuration
             for interface in self._interfaces:
                 address = '1'
                 sla_id = '1'
                 dhcpc6_config = read_file(f'/run/dhcp6c/dhcp6c.{interface}.conf')
 
                 # verify DHCPv6 prefix delegation
                 self.assertIn(f'prefix ::/{prefix_len} infinity;', dhcpc6_config)
 
                 for delegatee in delegatees:
                     self.assertIn(f'prefix-interface {delegatee}' + r' {', dhcpc6_config)
                     self.assertIn(f'ifid {address};', dhcpc6_config)
                     self.assertIn(f'sla-id {sla_id};', dhcpc6_config)
                     self.assertIn(f'sla-len {sla_len};', dhcpc6_config)
 
                     # increment sla-id
                     sla_id = str(int(sla_id) + 1)
                     # increment interface address
                     address = str(int(address) + 1)
 
             # Check for running process
             self.assertTrue(process_named_running('dhcp6c'))
 
             for delegatee in delegatees:
                 # we can already cleanup the test delegatee interface here
                 # as until commit() is called, nothing happens
                 section = Section.section(delegatee)
                 self.cli_delete(['interfaces', section, delegatee])