Hi everyone,
I’m running Proxmox VE 8.3.0 on a host called alpha.
The host sits on vmbr0 (vlan‑aware yes → physical NIC ens1f0np0).
I have a Debian VM (ID 2000) whose virtual NIC is attached to vmbr0 with VLAN tag 9 and configured as 191.7.184.13/28 with gateway 191.7.184.9.
What works:
- The Proxmox host itself can ping 191.7.184.9 without any issue.
What doesn’t:
- The VM can’t reach the gateway (or anything else).
ip neigh on the guest shows the gateway in incomplete state.
Checks already performed
- bridge ‑d vlan confirms the tap device (tap2000i0) is tagged as VLAN 9.
- tcpdump ‑i vmbr0 vlan 9 and tcpdump ‑i ens1f0np0 vlan 9 both show the guest’s ARP requests (“Who‑has 191.7.184.9?”) leaving the host with tag 9.
- No ARP reply ever returns.
- Creating a vmbr0.9 sub‑interface (with or without an IP) made no difference, so I removed it and stayed with vmbr0 only.
- The physical switch port that connects Proxmox is a trunk allowing VLAN 9.
So the frame clearly leaves Proxmox, VLAN tag intact, but the gateway never answers. At this point I suspect the problem is external (gateway or switch mis‑handling VLAN 9), yet I’d like to hear if I’m missing anything on the Proxmox side before I escalate to the network team.
Thanks in advance for any insight!
I’m running Proxmox VE 8.3.0 on a host called alpha.
The host sits on vmbr0 (vlan‑aware yes → physical NIC ens1f0np0).
I have a Debian VM (ID 2000) whose virtual NIC is attached to vmbr0 with VLAN tag 9 and configured as 191.7.184.13/28 with gateway 191.7.184.9.
What works:
- The Proxmox host itself can ping 191.7.184.9 without any issue.
What doesn’t:
- The VM can’t reach the gateway (or anything else).
ip neigh on the guest shows the gateway in incomplete state.
Checks already performed
- bridge ‑d vlan confirms the tap device (tap2000i0) is tagged as VLAN 9.
- tcpdump ‑i vmbr0 vlan 9 and tcpdump ‑i ens1f0np0 vlan 9 both show the guest’s ARP requests (“Who‑has 191.7.184.9?”) leaving the host with tag 9.
- No ARP reply ever returns.
- Creating a vmbr0.9 sub‑interface (with or without an IP) made no difference, so I removed it and stayed with vmbr0 only.
- The physical switch port that connects Proxmox is a trunk allowing VLAN 9.
So the frame clearly leaves Proxmox, VLAN tag intact, but the gateway never answers. At this point I suspect the problem is external (gateway or switch mis‑handling VLAN 9), yet I’d like to hear if I’m missing anything on the Proxmox side before I escalate to the network team.
Thanks in advance for any insight!
