root@:/var/log# ifdown vmbr1 --verbose && ifup vmbr1 --verbose
info: requesting link dump
info: requesting address dump
info: requesting netconf dump
info: loading builtin modules from ['/usr/share/ifupdown2/addons']
info: module openvswitch not loaded (module init failed: no /usr/bin/ovs-vsctl found)
info: module openvswitch_port not loaded (module init failed: no /usr/bin/ovs-vsctl found)
info: module ppp not loaded (module init failed: no /usr/bin/pon found)
info: module batman_adv not loaded (module init failed: no /usr/sbin/batctl found)
info: executing /sbin/sysctl net.bridge.bridge-allow-multiple-vlans
info: module mstpctl not loaded (module init failed: no /sbin/mstpctl found)
info: executing /bin/ip rule show
info: executing /bin/ip -6 rule show
info: address: using default mtu 1500
info: address: max_mtu undefined
info: executing /usr/sbin/ip vrf id
info: mgmt vrf_context = False
info: dhclient: dhclient_retry_on_failure set to 0
info: executing /bin/ip addr help
info: address metric support: OK
info: module ppp not loaded (module init failed: no /usr/bin/pon found)
info: module mstpctl not loaded (module init failed: no /sbin/mstpctl found)
info: module batman_adv not loaded (module init failed: no /usr/sbin/batctl found)
info: module openvswitch_port not loaded (module init failed: no /usr/bin/ovs-vsctl found)
info: module openvswitch not loaded (module init failed: no /usr/bin/ovs-vsctl found)
info: looking for user scripts under /etc/network
info: loading scripts under /etc/network/if-pre-up.d ...
info: loading scripts under /etc/network/if-up.d ...
info: loading scripts under /etc/network/if-post-up.d ...
info: loading scripts under /etc/network/if-pre-down.d ...
info: loading scripts under /etc/network/if-down.d ...
info: loading scripts under /etc/network/if-post-down.d ...
info: using mgmt iface default prefix eth
info: vmbr1: running ops ...
info: vmbr1: netlink: ip link set dev vmbr1 down
info: writing '0' to file /proc/sys/net/ipv4/conf/vmbr1/arp_accept
info: executing /etc/network/if-down.d/wpasupplicant
info: executing /etc/network/if-down.d/postfix
info: vmbr1: netlink: ip link del vmbr1
info: executing iptables -t nat -D POSTROUTING -s '10.10.10.0/24' -o eno1 -j MASQUERADE
info: executing /etc/network/if-post-down.d/wpasupplicant
info: exit status 0
info: requesting link dump
info: requesting address dump
info: requesting netconf dump
info: loading builtin modules from ['/usr/share/ifupdown2/addons']
info: module openvswitch not loaded (module init failed: no /usr/bin/ovs-vsctl found)
info: module openvswitch_port not loaded (module init failed: no /usr/bin/ovs-vsctl found)
info: module ppp not loaded (module init failed: no /usr/bin/pon found)
info: module batman_adv not loaded (module init failed: no /usr/sbin/batctl found)
info: executing /sbin/sysctl net.bridge.bridge-allow-multiple-vlans
info: module mstpctl not loaded (module init failed: no /sbin/mstpctl found)
info: executing /bin/ip rule show
info: executing /bin/ip -6 rule show
info: address: using default mtu 1500
info: address: max_mtu undefined
info: executing /usr/sbin/ip vrf id
info: mgmt vrf_context = False
info: dhclient: dhclient_retry_on_failure set to 0
info: executing /bin/ip addr help
info: address metric support: OK
info: module ppp not loaded (module init failed: no /usr/bin/pon found)
info: module mstpctl not loaded (module init failed: no /sbin/mstpctl found)
info: module batman_adv not loaded (module init failed: no /usr/sbin/batctl found)
info: module openvswitch_port not loaded (module init failed: no /usr/bin/ovs-vsctl found)
info: module openvswitch not loaded (module init failed: no /usr/bin/ovs-vsctl found)
info: looking for user scripts under /etc/network
info: loading scripts under /etc/network/if-pre-up.d ...
info: loading scripts under /etc/network/if-up.d ...
info: loading scripts under /etc/network/if-post-up.d ...
info: loading scripts under /etc/network/if-pre-down.d ...
info: loading scripts under /etc/network/if-down.d ...
info: loading scripts under /etc/network/if-post-down.d ...
info: using mgmt iface default prefix eth
info: processing interfaces file /etc/network/interfaces
info: vmbr1: running ops ...
info: vmbr1: netlink: ip link add dev vmbr1 type bridge
info: vmbr1: applying bridge settings
info: vmbr1: set bridge-fd 0
info: vmbr1: set bridge-mcsnoop yes
info: reading '/sys/class/net/vmbr1/bridge/stp_state'
info: vmbr1: netlink: ip link set dev vmbr1 type bridge (with attributes)
info: executing /sbin/sysctl net.mpls.conf.vmbr1.input=0
info: writing '1
' to file /proc/sys/net/ipv6/conf/vmbr1/forwarding
info: vmbr1: netlink: ip addr add 10.10.10.1/24 dev vmbr1
info: vmbr1: netlink: ip link set dev vmbr1 address ac:1f:6b:e9:7e:61
info: writing '0' to file /proc/sys/net/ipv4/conf/vmbr1/arp_accept
info: executing /etc/network/if-pre-up.d/wpasupplicant
info: vmbr1: netlink: ip link set dev vmbr1 up
info: executing /etc/network/if-up.d/wpasupplicant
info: executing /etc/network/if-up.d/postfix
info: executing echo 1 > /proc/sys/net/ipv4/ip_forward
info: executing iptables -t nat -A POSTROUTING -s '10.10.10.0/24' -o eno1 -j MASQUERADE
info: running upperifaces (parent interfaces) if available ..
info: exit status 0