O net.ipv6.conf.all.forwarding = 1 é equivalente a ativar o encaminhamento para todas as interfaces individuais?

Question

ou é a única maneira de habilitar o encaminhamento para o IPv6?

/proc/sys/net/ipv6/conf# grep '' */forwarding
all/forwarding:0
default/forwarding:1
eth0/forwarding:1
lo/forwarding:1
nat64/forwarding:1
tunl0/forwarding:1
veth_cm/forwarding:1
wifi0/forwarding:1
wlan0/forwarding:1

Não encaminha. Eu vejo pacotes no Wireshark, mas eles não alcançam ip6tables.

/proc/sys/net/ipv6/conf# grep '' */forwarding
all/forwarding:1
default/forwarding:1
eth0/forwarding:1
lo/forwarding:1
nat64/forwarding:1
tunl0/forwarding:1
veth_cm/forwarding:1
wifi0/forwarding:1
wlan0/forwarding:1

Agora a rede começa a funcionar.

/proc/sys/net/ipv6/conf# grep '' */forwarding
all/forwarding:1
default/forwarding:0
eth0/forwarding:0
lo/forwarding:0
nat64/forwarding:0
tunl0/forwarding:0
veth_cm/forwarding:0
wifi0/forwarding:0
wlan0/forwarding:0

A rede ainda funciona. Esses switches individuais por interface são usados? Pode ser um bug do kernel do Linux (agora executando a versão 4.9.5).

    

Answer 1

Parece que foi desenvolvido para funcionar de maneira diferente em comparação com */forwarding e all/forwarding do IPv4:

Em link :

conf/all/forwarding - BOOLEAN
    Enable global IPv6 forwarding between all interfaces.

    IPv4 and IPv6 work differently here; e.g. netfilter must be used
    to control which interfaces may forward packets and which not.

    This also sets all interfaces' Host/Router setting
    'forwarding' to the specified value.  See below for details.

    This referred to as global forwarding.

forwarding - INTEGER
    Configure interface-specific Host/Router behaviour.

    Note: It is recommended to have the same setting on all
    interfaces; mixed router/host scenarios are rather uncommon.

    Possible values are:
        0 Forwarding disabled
        1 Forwarding enabled

    FALSE (0):

    By default, Host behaviour is assumed.  This means:

    1. IsRouter flag is not set in Neighbour Advertisements.
    2. If accept_ra is TRUE (default), transmit Router
       Solicitations.
    3. If accept_ra is TRUE (default), accept Router
       Advertisements (and do autoconfiguration).
    4. If accept_redirects is TRUE (default), accept Redirects.

    TRUE (1):

    If local forwarding is enabled, Router behaviour is assumed.
    This means exactly the reverse from the above:

    1. IsRouter flag is set in Neighbour Advertisements.
    2. Router Solicitations are not sent unless accept_ra is 2.
    3. Router Advertisements are ignored unless accept_ra is 2.
    4. Redirects are ignored.

    Default: 0 (disabled) if global forwarding is disabled (default),
         otherwise 1 (enabled).

Portanto, a interface forwarding é usada apenas para funções auxiliares, como vários comportamentos de sinalizadores e pacotes especiais, não para decidir se os pacotes serão retransmitidos ou não.