Linux kernel 4.9 não respondendo à solicitação do vizinho

Question

Eu tenho essa pequena rede onde o kernel Linux 4.9 atua como um roteador v6. Existem dois outros servidores conectados a este roteador e ambos têm endereço IPv6 configurado nas interfaces conectadas a este roteador. O prefixo do endereço é fc::/8 .

Mas quando tento fazer ping de um servidor para outro, ele falha com o erro "Endereço inacessível"

Então, tentei fazer ping no endereço v6 local no roteador, que também falha com o erro "Endereço inacessível"

Quando eu verifico as capturas de pacotes, vejo o servidor tentando obter o endereço MAC usando a solicitação do vizinho, mas o Linux Router não está respondendo a isso. Eu tenho o encaminhamento v6 ativado.

tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on enp2s0, link-type EN10MB (Ethernet), capture size 262144 bytes
17:53:02.828354 IP6 fdcd:dead:beef:babe::2 > ff02::1:ff00:3: ICMP6, neighbor solicitation, who has fdcd:dead:beef:cafe::3, length 32
17:53:03.869313 IP6 fdcd:dead:beef:babe::2 > ff02::1:ff00:3: ICMP6, neighbor solicitation, who has fdcd:dead:beef:cafe::3, length 32
17:53:04.907996 IP6 fdcd:dead:beef:babe::2 > ff02::1:ff00:3: ICMP6, neighbor solicitation, who has fdcd:dead:beef:cafe::3, length 32
17:53:05.947761 IP6 fdcd:dead:beef:babe::2 > ff02::1:ff00:3: ICMP6, neighbor solicitation, who has fdcd:dead:beef:cafe::3, length 32
17:53:06.987722 IP6 fdcd:dead:beef:babe::2 > ff02::1:ff00:3: ICMP6, neighbor solicitation, who has fdcd:dead:beef:cafe::3, length 32
17:53:08.027434 IP6 fdcd:dead:beef:babe::2 > ff02::1:ff00:3: ICMP6, neighbor solicitation, who has fdcd:dead:beef:cafe::3, length 32
17:53:09.067203 IP6 fdcd:dead:beef:babe::2 > ff02::1:ff00:3: ICMP6, neighbor solicitation, who has fdcd:dead:beef:cafe::3, length 32
17:53:10.107501 IP6 fdcd:dead:beef:babe::2 > ff02::1:ff00:3: ICMP6, neighbor solicitation, who has fdcd:dead:beef:cafe::3, length 32
17:53:11.146856 IP6 fdcd:dead:beef:babe::2 > ff02::1:ff00:3: ICMP6, neighbor solicitation, who has fdcd:dead:beef:cafe::3, length 32
17:53:12.186701 IP6 fdcd:dead:beef:babe::2 > ff02::1:ff00:3: ICMP6, neighbor solicitation, who has fdcd:dead:beef:cafe::3, length 32
17:53:13.226875 IP6 fdcd:dead:beef:babe::2 > ff02::1:ff00:3: ICMP6, neighbor solicitation, who has fdcd:dead:beef:cafe::3, length 32
17:53:14.266411 IP6 fdcd:dead:beef:babe::2 > ff02::1:ff00:3: ICMP6, neighbor solicitation, who has fdcd:dead:beef:cafe::3, length 32
17:53:15.306211 IP6 fdcd:dead:beef:babe::2 > ff02::1:ff00:3: ICMP6, neighbor solicitation, who has fdcd:dead:beef:cafe::3, length 32
17:53:16.346467 IP6 fdcd:dead:beef:babe::2 > ff02::1:ff00:3: ICMP6, neighbor solicitation, who has fdcd:dead:beef:cafe::3, length 32

Interfaces do lado do roteador:

3: enp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:e0:67:09:97:85 brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.1/24 brd 192.168.1.255 scope global enp2s0
       valid_lft forever preferred_lft forever
    inet6 fdcd:dead:beef:babe::3/64 scope global
       valid_lft forever preferred_lft forever
    inet6 fe80::2e0:67ff:fe09:9785/64 scope link
       valid_lft forever preferred_lft forever

4: enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:e0:67:09:97:86 brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.1/24 brd 192.168.100.255 scope global enp3s0
       valid_lft forever preferred_lft forever
    inet6 fdcd:dead:beef:cafe::3/64 scope global
       valid_lft forever preferred_lft forever
    inet6 fe80::2e0:67ff:fe09:9786/64 scope link
       valid_lft forever preferred_lft forever

Configuração de roteamento no lado do roteador:

::1 dev lo proto kernel metric 256  pref medium
0:0:0:a::/64 dev enp4s0 proto kernel metric 256  expires 86348sec pref medium
fdcd:dead:beef:babe::/64 dev enp2s0 proto kernel metric 256  pref medium
fdcd:dead:beef:cafe::/64 dev enp3s0 proto kernel metric 256  pref medium
fe80::/64 dev enp2s0 proto kernel metric 256  pref medium
fe80::/64 dev enp3s0 proto kernel metric 256  pref medium
fe80::/64 dev enp4s0 proto kernel metric 256  pref medium
fe80::/64 dev enp1s0 proto kernel metric 256  pref medium
default via fe80::6238:e0ff:fed0:1db9 dev enp4s0 proto ra metric 1024  expires 1748sec hoplimit 64 pref medium

Interface do Host 1:

2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether b8:27:eb:0d:e9:58 brd ff:ff:ff:ff:ff:ff
    inet6 fdcd:dead:beef:babe::2/64 scope global
       valid_lft forever preferred_lft forever
    inet6 fe80::ba27:ebff:fe0d:e958/64 scope link
       valid_lft forever preferred_lft forever

Configuração de roteamento:

fdcd:dead:beef:babe::/64 dev eth0 proto kernel metric 256  pref medium
fdcd:dead:beef:cafe::/64 dev eth0 metric 1024  pref medium
fe80::/64 dev eth1 proto kernel metric 256  pref medium
fe80::/64 dev eth0 proto kernel metric 256  pref medium
default via fdcd:dead:beef:babe::3 dev eth0 metric 1024  pref medium

Interface do Host 2:

3: enp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:e0:67:09:97:81 brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.2/24 brd 192.168.100.255 scope global enp2s0
       valid_lft forever preferred_lft forever
    inet6 fdcd:dead:beef:cafe::2/64 scope global
       valid_lft forever preferred_lft forever
    inet6 fe80::2e0:67ff:fe09:9781/64 scope link
       valid_lft forever preferred_lft forever

Configuração de roteamento:

fdcd:dead:beef:babe::/64 dev enp2s0 metric 1024  pref medium
fdcd:dead:beef:cafe::/64 dev enp2s0 proto kernel metric 256  pref medium
fe80::/64 dev enp2s0 proto kernel metric 256  pref medium
fe80::/64 dev enp1s0 proto kernel metric 256  pref medium

Rede:

Host A (eth0) <----> L2 switch A <---> Linux v6 router (enp2s0)

Host B (enp2s0) <----> L2 switch B <---> Linux v6 router (enp3s0)

Configuração do firewall:

root@XXXXX:~# iptables -S
-P INPUT ACCEPT
-P FORWARD ACCEPT
-P OUTPUT ACCEPT

Qualquer ajuda é muito apreciada