Le DELL s'appelle firewall, l'ACER laptop1
Les tests depuis DELL -> ACER

root@firewall:~# traceroute -n laptop1
traceroute to laptop1.bureau (192.168.0.2), 30 hops max, 38 byte packets
1 192.168.0.2 0.137 ms 0.089 ms 0.083 ms
root@firewall:~# ping laptop1
PING laptop1.bureau (192.168.0.2) 56(84) bytes of data.
64 bytes from laptop1.bureau (192.168.0.2): icmp_seq=1 ttl=64 time=0.099 ms
64 bytes from laptop1.bureau (192.168.0.2): icmp_seq=2 ttl=64 time=0.131 ms
64 bytes from laptop1.bureau (192.168.0.2): icmp_seq=3 ttl=64 time=0.129 ms

--- laptop1.bureau ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 1998ms
rtt min/avg/max/mdev = 0.099/0.119/0.131/0.019 ms

Les test ACER -> DELL

root@laptop1:~$ traceroute firewall
traceroute to firewall.bureau (192.168.0.1), 30 hops max, 38 byte packets
1 firewall.bureau (192.168.0.1) 0.218 ms 0.083 ms 0.074 ms
root@laptop1:~$ traceroute -n firewall
traceroute to firewall.bureau (192.168.0.1), 30 hops max, 38 byte packets
1 192.168.0.1 0.166 ms 0.078 ms 0.073 ms
root@laptop1:~$ ping firewall
PING firewall.bureau (192.168.0.1) 56(84) bytes of data.
64 bytes from firewall.bureau (192.168.0.1): icmp_seq=1 ttl=64 time=0.133 ms
64 bytes from firewall.bureau (192.168.0.1): icmp_seq=2 ttl=64 time=0.134 ms
64 bytes from firewall.bureau (192.168.0.1): icmp_seq=3 ttl=64 time=0.136 ms

--- firewall.bureau ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 1998ms
rtt min/avg/max/mdev = 0.133/0.134/0.136/0.009 ms

Ces commandes ne montrent pas que je passe par l'interface sur le NET
Le traceroute vers mon @IP du net sur l'ACER remonte un seul
routeur avec un temps de 0.205ms.