Network – Can DHCP in a network interface assign a local IP address that overlaps with the subnet of another interface?

iface eth0 inet dhcp

iface eth1 inet static

Can a host connect? eth0 and get assigned an address that is part of eth1Subnet domain (everything from to

What negative consequences does this have in practice and is the expected (wrong) behavior deterministic?

Is there anything that can be done to prevent this while leaving the hotel? static and dhcp Methods unchanged? I could not find anything on the manpage.

Linear Algebra – Isotropic, symmetric tensors assign symmetric tensors to a zero offset

I go through Chorins and Marsden's derivation of the Navier-Stokes equations in A mathematical introduction to fluid mechanics, There are three assumptions about the Cauchy stress tensor $ pmb sigma $ (which I paraphrase):

1) $ pmb sigma $ depends only on the speed gradient $ nabla mathbf {u} $, So written as a linear transformation $ pmb sigma = pmb sigma ( nabla mathbf {u}) $

2) $ pmb sigma $ is an isotropic tensor function (rotationally invariant), so that $$ pmb sigma (U nabla mathbfu U ^ T) = U pmb sigma ( nabla mathbfu) U ^ T $$ for a suitable orthogonal matrix $ U $,

3) $ pmb sigma $ is symmetrical.

Having stated these assumptions, they conclude that 3) and 2) show that $ pmb sigma $ can only depend on the symmetric part of $ nabla mathbf u $, In other words, when you write $$ nabla mathbf u = D + W $$ Where $ D = frac 1 2 ( nabla mathbfu + nabla mathbfu ^ T) $ (the symmetric part of $ nabla mathbf u $) and $ W = frac 1 2 ( nabla mathbf u – nabla mathbf u ^ T) $ (the antisymmetric part of $ nabla mathbf u $), then $ pmb sigma (W) = mathbf 0 $i.e. $ pmb sigma $ assigns second order antisymmetric tensors to the zero order tensor.

I'm not sure how the argument above works, and would be happy to help if I could see it.

Note: I have seen arguments that use the fact that $ pmb sigma $ must fulfill in component form

$$ sigma_ {ij} = -p delta_ {ij} + C_ {ijrs} u_ {r, s} $$

Where $ p $ is the pressure and it ends up being the tensor fourth order $ mathbf $ must take a special form (since it is an isotropic tensor symmetric in the first two indices and the last two indices). You can derive this from this special form $ pmb sigma $ assigns the zero order tensor to a second order tensor that has an offset.

I am interested in seeing an argument that does not rely on component analysis and does not immediately jump to the specific representation of second-order isotropic tensor functions with respect to their major invariants.

java – I can not assign different clients to an array and can not change values ​​with .set (CRUD)

Hello, I'm having trouble creating a crud. I've created a method where the user enters values ​​for the ID, name, and email variables. So the idea was to register this data in an array list for each user and then be able to see every registered user and I can also change the data (name and / or email) by ID, but my first problem is already if I'm going to show the registered users, the program is printing several of the most recent inputs and not different users and lastly my problem is not method to update some users by its ID, I am not able to write the correct code for it , thanks, if you can help me, thank you!

Below are the codes:


public class Loja {
    public static void main(String() args) {
        Pedido pedidoInvocado = new Pedido();


import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Cliente {
    // Definindo atributos da classe Cliente
        private int clienteId;
        private String Nome;
        private String Email;

    // Get and Setters
        // clienteId
            public int getClienteId() {
                return clienteId;

            public void setClienteId(int clienteId) {
                this.clienteId = clienteId;
        // Nome
            public String getNome() {
                return Nome;

            public void setNome(String nome) {
                Nome = nome;
        // Email
            public String getEmail() {
                return Email;

            public void setEmail(String email) {
                Email = email;

    // Metodos
        // Metodo para o usuario definir o id, nome e email
            public void atribuirCliente(){
                // Criação do scanner
                    Scanner inputInt = new Scanner(;
                    Scanner inputString = new Scanner(;
                // Criação e atribuição das variaveiS
                        System.out.print("DIGITE O SEU ID: ");
                            int clienteId = inputInt.nextInt();
                        System.out.print("DIGITE O SEU NOME: ");
                            String Nome = inputString.nextLine();
                        System.out.print("DIGITE O SEU EMAIL: ");
                            String Email = inputString.nextLine();
                // Setters com os valores das variaaveis anteriores



import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Pedido {
    // Definindo atributos da classe Pedido
        private int pedidoId;
        private String dataEmissao;
        private float valorTotal;

    // Invocando Objetos
        Cliente clienteInvocado = new Cliente();
        itemPedido itemPedidoInvocado = new itemPedido();

    // Criando ArrayList
        List listaDeClientes = new ArrayList();

    // Get and Setters
        // pedidoId
            public int getPedidoId() {
                return pedidoId;

            public void setPedidoId(int pedidoId) {
                this.pedidoId = pedidoId;
        // dataEmissao
            public String getDataEmissao() {
                return dataEmissao;

            public void setDataEmissao(String dataEmissao) {
                this.dataEmissao = dataEmissao;
        // valorTotal
            public float getValorTotal() {
                return valorTotal;

            public void setValorTotal(float valorTotal) {
                this.valorTotal = valorTotal;

    // Metodos

        // Metodo para inserir clientes (INSERT)
            public void inserirCliente(){
                // Criação do Scanner
                    Scanner inputInt = new Scanner(;
                // Criação da variavel Do While
                    int Escolha = 0;
                do {
                    // Invocando o metodo de ler os dados do cliente
                    // Inserindo clientes e tratando erros
                        Cliente cliente = new Cliente();
                        System.out.println(" ");
                        System.out.println("CLIENTE CADASTRADO COM SUCESSO!n");
                        System.out.print("1 - CADASTRAR NOVAMENTE | 2 - TERMINAR CADASTROnRESPOSTA: ");
                            Escolha = inputInt.nextInt();
                    } catch (Exception err){
                        System.out.println(" ");
                        System.out.println("ERRO AO CADASTRAR CLIENTE: " + err);
                } while (Escolha != 2);

        // Metodo para listar clientes (READ)
            public void listarCliente(){
                for (Cliente cliente : listaDeClientes){
                    System.out.println("ID: " + clienteInvocado.getClienteId() + " | NOME: " + clienteInvocado.getNome() + " | EMAIL: " + clienteInvocado.getEmail());

        // Metodo para deletar clientes por ID (DELETE)
            public void deletarCliente(){
                // Criação do scanner
                    Scanner inputInt = new Scanner(;
                // Criação e atribuição das variaveis
                    System.out.print("DIGITE O ID QUE DESEJA DELETAR: ");
                        int ID = inputInt.nextInt();
                // Deletando do ArrayList
                    for (Cliente cliente : listaDeClientes){
                        if (clienteInvocado.getClienteId() == ID){
                        // Lista todos os clientes cadastrados novamente apos à exclusão


        // Metodo para alterar clientes por ID (UPDATE)
            public void alterarCliente(){
                // Criação do scanner
                    Scanner inputInt = new Scanner(;
                // Criação e atribuição das variaveis
                    System.out.print("DIGITE O ID QUE DESEJA MODIFICAR: ");
                        int ID = inputInt.nextInt();
                // Deletando do ArrayList
                    for (Cliente cliente : listaDeClientes){
                        if (clienteInvocado.getClienteId() == ID){
                            listaDeClientes.set(ID, cliente);
                        // Lista todos os clientes cadastrados novamente apos à exclusão

8 – Is it possible to assign a temporary role to an anonymous session?

The use case is to give an "anonymous" user a set of permissions, ie we do not know who he is and he has not logged in. We only have the IP range to confirm where it came from (yes, I know you … it's not a system I would design :)).

I do not necessarily know what permissions these users need across the board, that is, access to specific node types, or access to specific file locations. It is an evolving set of permissions that would later be configured as a role.

Is it possible to define a role and then temporarily assign it to anonymous meetings that meet our criteria? I've tried to check with an EventSubscriber every time our module loads, but that does not work, because obviously we can not really "save" an anonymous user; H .:

class CivicrmIpAccessSubscriber implements EventSubscriberInterface {

  public function CivicrmIpAccessLoad(GetResponseEvent $event) {
    $proxy = Drupal::currentUser();
    $roles = $proxy->getRoles();
    if ($roles === ('anonymous')) {
//Business logic to determine if a user gets access would go here
      $user = User::load($proxy->id());
//This user save doesn't work, and I wouldn't have really expected it to but I tried it

   * {@inheritdoc}
  public static function getSubscribedEvents() {
    $events(KernelEvents::REQUEST)() = ('CivicrmIpAccessLoad', 250);
    return $events;


Is there a good way to achieve something like this for a session? I have the feeling that an anonymous user is barking the wrong tree and the session is correct, but I'm not sure how to interact with the access from there.

finder – assign nothing but default, which opens with the application

Usually I have a bunch of audio files (.mp3) with my music and some other non-audio files (.asd) in the same directory. To quickly play music, I simply select all in the finder and press cmd + o to open them in my standard application (vlc). The ASD files are also opened, but I never want to open them. They are used by the ableton live application, but are not intended to be opened.

is it possible to assign "nothing" as the default application for .asd files? I think maybe with defaults or another command line trick, if necessary.

Keyboard – Assign the Debug ("Step Into") function key to the Mac Excel Visual Basic Editor

I've tried many things to assign a 1-key shortcut to the "Step Into" debugging feature in the VBA Editor for Mac Excel (Mac VBE). I asked a question about stack overflow, but in my experience, Macintosh-related issues are often not resolved there, as in this case.

Below are screenshots showing a try to reassign F8 Key (used in Windows for this). Although it looks like it will work, pressing the key during debugging will not work (although the default is awkward shift-cmd-i still works). There are other "solutions" to this kind of problem that do not work for me. Namely with the FN key in combination with F8 or check the "Use F1.F2,etc. I also tried using a utility called FunctionFlip, but like others, it did not work for me.

Enter image description here

Enter image description here

I am not bound F8and would like others like F5. F6 or F7 which are already used in the Mac VBE. I say that because, after a comment by Emilio F8 is something special on the Mac. But when I tried it F5For example, it failed too.

I'm using a non-touch MacBook pro (which replaces the function keys to my knowledge) and use both a notebook keyboard and an external (Mac) keyboard I bought in 2019.

Can you assign different sounds for notifications to different applications?

I use and I hear notification sounds, but I do not know which application they come from because all apps have the same sound. Apparently there are no badges available for apps like Slack that help me determine if I've received a message. I'm wondering if it's even possible to give each application a different sound that emits a sound for the notification setting. That would be much easier to know which app is issuing a notification.

DHCP – assign IPv6 based on the MAC address?

The block assigned to me is 2001: 41d0: 8: 7d1 :: / 64 Gateway 2001: 41d0: 8: 7ff: ff: ff: ff: ff (OVH IP)

For some reason, DHCP automatically assigns IPv6 before I even try to add any of them (fe80 :: ff: fed2: 9128/64).


auto lo
iface lo inet loopback

iface eno1 inet manual

auto vmbr0
iface vmbr0 inet static
        netmask  24
        bridge-ports eno1
        bridge-stp off
        bridge-fd 0

iface vmbr0 inet6 static
        address 2001:41d0:8:7d1::1
        netmask 64
        post-up /sbin/ip -f inet6 route add 2001:41d0:8:7ff:ff:ff:ff:ff dev vmbr0
        post-up /sbin/ip -f inet6 route add default via 2001:41d0:8:7ff:ff:ff:ff:ff
        pre-down /sbin/ip -f inet6 route del default via 2001:41d0:8:7ff:ff:ff:ff:ff200
        pre-down /sbin/ip -f inet6 route del 2001:41d0:8:7ff:ff:ff:ff:ff dev vmbr0


# Defaults for isc-dhcp-server (sourced by /etc/init.d/isc-dhcp-server)

# Path to dhcpd's config file (default: /etc/dhcp/dhcpd.conf).

# Path to dhcpd's PID file (default: /var/run/

# Additional options to start dhcpd with.
#       Don't use options -cf or -pf here; use DHCPD_CONF/ DHCPD_PID instead

# On what interfaces should the DHCP server (dhcpd) serve DHCP requests?
#       Separate multiple interfaces with spaces, e.g. "eth0 eth1".


ddns-update-style none;
default-lease-time 600;
max-lease-time 7200;
log-facility local7;
option rfc3442-classless-static-routes code 121 = array of integer 8;
option ms-classless-static-routes code 249 = array of integer 8;

subnet netmask {
 default-lease-time 21600000;
 max-lease-time 432000000;
 option routers;
 option domain-name-servers,;
 option rfc3442-classless-static-routes 32, 176, 31, 246, 254, 0, 0, 0, 0, 0, 176, 31, 246, 254;
 option ms-classless-static-routes 32, 176, 31, 246, 254, 0, 0, 0, 0, 0, 176, 31, 246, 254;
  host 1 {hardware ethernet 02:00:00:d2:91:28;fixed-address;option subnet-mask;option routers;}
  host 2 {hardware ethernet 02:00:00:59:9f:96;fixed-address;option subnet-mask;option routers;}
  host 3 {hardware ethernet 02:00:00:b4:92:6e;fixed-address;option subnet-mask;option routers;}
  host 4 {hardware ethernet 02:00:00:9e:f6:3e;fixed-address;option subnet-mask;option routers;}


# The ddns-updates-style parameter controls whether or not the server will
# attempt to do a DNS update when a lease is confirmed.
ddns-update-style none;

# Option definitions common to all supported networks...
default-lease-time 600;
max-lease-time 7200;

# This DHCP server is the official DHCP server for the local network

# Use this to send dhcp log messages to a different log file (you also
# have to hack syslog.conf to complete the redirection).
log-facility local7;

# Subnet declaration
host1 {hardware ethernet 02:00:00:59:9f:96;fixed-address6 2001:41d0:8:7d1:8888:9999:0000:2222;option dhcp6.domain-search "netprobe.local";}