Bonsoir,
Je viens de changer de configuration pour mon serveur proxmox, passant d'une carte mère AM2 (athlon x2) à du 775 (Xeon) et je n'ai plus de réseau, uniquement sur les machine virtuelles.
J'ai bien évidemment adapté l'interface qui est passé de enp3s0 à enp2s0 dans /etc/network/interfaces et j'ai bien du réseau via proxmox et les conteneurs, mais sur les VM, rien ne passe... Les IP n'ont pas bougées et tout est bien détecté et up.
Ai-je oublié un truc ? 
Merci
root@pve:~# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: enp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vmbr0 state UP group default qlen 1000
    link/ether 00:22:15:xx:xx:xx brd ff:ff:ff:ff:ff:ff
3: vmbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 00:22:15:xx:xx:xx brd ff:ff:ff:ff:ff:ff
    inet 192.168.2.2/24 brd 192.168.2.255 scope global vmbr0
       valid_lft forever preferred_lft forever
    inet6 fe80::222:15ff:fe8b:2b2a/64 scope link 
       valid_lft forever preferred_lft forever
root@pve:~# ping 192.168.2.7
PING 192.168.2.7 (192.168.2.7) 56(84) bytes of data.
From 192.168.2.2 icmp_seq=1 Destination Host Unreachable
From 192.168.2.2 icmp_seq=2 Destination Host Unreachable
From 192.168.2.2 icmp_seq=3 Destination Host Unreachable
From 192.168.2.2 icmp_seq=4 Destination Host Unreachable
From 192.168.2.2 icmp_seq=5 Destination Host Unreachable
From 192.168.2.2 icmp_seq=6 Destination Host Unreachable
From 192.168.2.2 icmp_seq=7 Destination Host Unreachable
From 192.168.2.2 icmp_seq=8 Destination Host Unreachable
From 192.168.2.2 icmp_seq=11 Destination Host Unreachable
^X^X^C
--- 192.168.2.7 ping statistics ---
15 packets transmitted, 0 received, +9 errors, 100% packet loss, time 342ms 
root@pve:~# ping google.com
PING google.com (216.58.214.78) 56(84) bytes of data.
64 bytes from par10s39-in-f14.1e100.net (216.58.214.78): icmp_seq=1 ttl=114 time=30.2 ms
64 bytes from par10s39-in-f14.1e100.net (216.58.214.78): icmp_seq=2 ttl=114 time=30.3 ms
64 bytes from par10s39-in-f14.1e100.net (216.58.214.78): icmp_seq=3 ttl=114 time=29.8 ms
^C
--- google.com ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 5ms
rtt min/avg/max/mdev = 29.755/30.078/30.310/0.235 ms