if [[ $reason =~ (EXPIRE|FAIL|RELEASE|STOP) ]]; then
    # delete dynamic nameservers from a configuration if lease was deleted
    logmsg info "Deleting nameservers with tag \"dhcp-${interface}\" via vyos-hostsd-client"
    vyos-hostsd-client --delete-name-servers --tag dhcp-${interface}
    # try to delete default ip route (NOTE: here we use 'ip' wrapper, therefore a route will be actually deleted via /usr/sbin/ip or vtysh, according to the system state)
    for router in $old_routers; do
        logmsg info "Deleting default route: via $router dev ${interface}"
        ip -4 route del default via $router dev ${interface}
    done
fi

if [[ $reason =~ (EXPIRE6|RELEASE6|STOP6) ]]; then
    # delete dynamic nameservers from a configuration if lease was deleted
    logmsg info "Deleting nameservers with tag \"dhcpv6-${interface}\" via vyos-hostsd-client"
    vyos-hostsd-client --delete-name-servers --tag dhcpv6-${interface}
fi