Connection with host issue in 'connectivity/networking/networking_with_multiple_instances'

[gabilm]

Hi all.

Just my first approach to zephyr ...

I have tested the "networking_with_multiple_instances" using the coap_server and client_client examples. it work fine. Great!.

With the given configuration example, client and server can connect to each other, but the host (Ubuntu 22.04.4 server) can not ping6 o run a coap_client .

For example:
@ubuntu-zephyr:~/zephyrproject/tools/net-tools$ ping6 2001:db8:100::1
PING 2001:db8:100::1(2001:db8:100::1) 56 data bytes
From 2001:db8:100::2 icmp_seq=1 Destination unreachable: Address unreachable
From 2001:db8:100::2 icmp_seq=2 Destination unreachable: Address unreachable
From 2001:db8:100::2 icmp_seq=3 Destination unreachable: Address unreachable

m@ubuntu-zephyr:~$ sudo tcpdump -i zeth-br
tcpdump: verbose output suppressed, use -v[v]... for full protocol decode
listening on zeth-br, link-type EN10MB (Ethernet), snapshot length 262144 bytes

10:30:39.350106 IP6 2001:db8:100::1 > ff02::1:ff00:2: ICMP6, neighbor solicitation, who has ubuntu-zephyr, length 32
10:30:39.350212 IP6 2001:db8:100::1 > ubuntu-zephyr: ICMP6, neighbor advertisement, tgt is 2001:db8:100::1, length 32
10:30:40.378649 IP6 2001:db8:100::1 > ubuntu-zephyr: ICMP6, neighbor advertisement, tgt is 2001:db8:100::1, length 32
10:30:41.402617 IP6 2001:db8:100::1 > ubuntu-zephyr: ICMP6, neighbor advertisement, tgt is 2001:db8:100::1, length 32
10:30:42.426850 IP6 2001:db8:100::1 > ubuntu-zephyr: ICMP6, neighbor advertisement, tgt is 2001:db8:100::1, length 32

The coap_server can ping6 the coap_client, but not the host (zeth.1):
uart:~$ net ping 2001:db8:100::2
PING 2001:db8:100::2
Ping timeout

I assume this is the expected behaviour but, how can I enable the ipv6 connection between the coap_server/client nodes and the host? I have been playing with the bridge interface but with no result.

Thanks in advance.