no traffic between LXC containers


New Member
Oct 6, 2023
Dear all,
i am running Proxmox VE 8.0.4 on an Intel NUC NUC6CAYH and have a strange problem:
there are two LXC containers (created from debian-11-standard_11.7_1)
they are on the same subnet, same network assigned to them: vmbr0
they can be accessed from everywhere as expected and can reach internet and so on.
all fine.

BUT: they can´t reach each other. not even with ping.

container a does not have an entry in the ARP table for container b.
in tcpdump container a does not even generate ARP traffic to look for container b.

I am new to Proxmox, so maybe this is expected and just needs some configuration?

would be great if someone could help.


Have you checked the firewall?

Firewall is disabled at datacenter level.

However, on the host its also turned off:
root@proxmox0:~# pve-firewall status
Status: disabled/stopped

Same for the lxc containers:
"Firewall: no"

What else can I check?
Last edited:


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