[PVE-User] ARP issue between lxc containers on PX 4.2

[Guillaume]

Hello,

I'm running Proxmox 4.2-15, with a fresh install :

# pveversion -v
proxmox-ve: 4.2-56 (running kernel: 4.4.13-1-pve)
pve-manager: 4.2-15 (running version: 4.2-15/6669ad2c)
pve-kernel-4.4.13-1-pve: 4.4.13-56
pve-kernel-4.2.8-1-pve: 4.2.8-41
lvm2: 2.02.116-pve2
corosync-pve: 2.3.5-2
libqb0: 1.0-1
pve-cluster: 4.0-42
qemu-server: 4.0-83
pve-firmware: 1.1-8
libpve-common-perl: 4.0-70
libpve-access-control: 4.0-16
libpve-storage-perl: 4.0-55
pve-libspice-server1: 0.12.5-2
vncterm: 1.2-1
pve-qemu-kvm: 2.5-19
pve-container: 1.0-70
pve-firewall: 2.0-29
pve-ha-manager: 1.0-32
ksm-control-daemon: 1.2-1
glusterfs-client: 3.5.2-2+deb8u2
lxc-pve: 1.1.5-7
lxcfs: 2.0.0-pve2
cgmanager: 0.39-pve1
criu: 1.6.0-1
zfsutils: 0.6.5.7-pve10~bpo80

# sysctl -p
net.ipv6.conf.all.autoconf = 0
net.ipv6.conf.default.autoconf = 0
net.ipv6.conf.vmbr0.autoconf = 0
net.ipv6.conf.all.accept_ra = 0
net.ipv6.conf.default.accept_ra = 0
net.ipv6.conf.vmbr0.accept_ra = 0
net.ipv6.conf.vmbr0.accept_ra = 0
net.ipv6.conf.vmbr0.autoconf = 0


I'm only using lxc containers.

Host have 2 networks interfaces, vmbr0 with public ip 164.132.161.131/32 
(gtw 164.132.161.254) and vmbr2 with private ip (ovh vrack 2) 
192.168.30.3/24.
Containers have public interface eth0 with public ip address (based on 
vmbr0) and eth1 with private ip address (based on vmbr2) :

* LXC1
     eth0 : 51.254.231.80/28
     eth1 : 192.168.30.101/24

* LXC2
     eth0 : 51.254.231.81/28
     eth1 : 192.168.30.102/24

They both have access to the net, but can't talk to each other, whatever 
network interface (public or private) i'm using.
Same issue with firewall down on the node (on the 3 levels).

# Ping from LXC1 51.254.231.80 to LXC2 51.254.231.81 : tcpdump from LXC1
15:54:00.810638 ARP, Request who-has 164.132.161.250 tell 
164.132.161.252, length 46

# Ping from LXC1 192.168.30.101 to LXC2 192.168.30.102 (vrack) : tcpdump 
from LXC1
15:54:52.260934 ARP, Request who-has 192.168.30.102 tell 192.168.30.3, 
length 28
15:54:52.260988 ARP, Reply 192.168.30.102 is-at 62:31:32:34:65:61 (oui 
Unknown), length 28
15:54:52.575082 IP 192.168.30.102 > 192.168.30.101: ICMP echo request, 
id 1043, seq 3, length 64
15:54:53.583057 IP 192.168.30.102 > 192.168.30.101: ICMP echo request, 
id 1043, seq 4, length 64

# Ping from LXC1 192.168.30.101 to LXC2 192.168.30.102 (vrack) : tcpdump 
from Proxmox
17:56:05.861665 ARP, Request who-has 192.168.30.101 tell 192.168.30.102, 
length 28
17:56:05.861688 ARP, Reply 192.168.30.101 is-at 62:31:32:34:65:61 (oui 
Unknown), length 28
17:56:06.860925 ARP, Request who-has 192.168.30.101 tell 192.168.30.102, 
length 28
17:56:06.860998 ARP, Reply 192.168.30.101 is-at 62:31:32:34:65:61 (oui 
Unknown), length 28

Any idea ?

Thanks,

Guillaume