Problem: Lost connection when adding VLAN to Proxmox

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spablos1

New Member
Aug 20, 2025
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Hello everyone,

I’m setting up a Proxmox node with two networks:
• 10.10.64.0/24 - Management (host access, WebUI, SSH, etc.)
• 10.10.106.0/24 - For cluster traffic and for VMs

My physical NIC is eno12399np0, connected to a switch port configured as a trunk with VLAN 1 (untagged, management) and VLAN 1006 (tagged).

This is my current /etc/network/interfaces configuration:

Code: 
auto lo
iface lo inet loopback

iface eno12399np0 inet manual

iface eno8303 inet manual

iface eno8403 inet manual

iface ens1f1np1 inet manual

iface eno12409np1 inet manual

iface ens1f0np0 inet manual

auto vmbr0
iface vmbr0 inet static
        address 10.10.64.62/24
        gateway 10.10.64.13
        bridge-ports eno12399np0
        bridge-stp off
        bridge-fd 0

auto vmbr0.1006
iface vmbr0.1006 inet static
        address 10.10.106.152/24

source /etc/network/interfaces.d/*
root@pvemad1:~#

• The management works fine on 10.10.64.62:8006.
• As soon as I add the vmbr0.1006 interface, I lose connectivity to the WebUI / SSH...
• I only want the host management to stay at 10.10.64.62, while using 10.10.106.152 only for the cluster network and to allow VMs to run on VLAN 1006.

What I tried:
• Setting bridge-vlan-aware yes with bridge-vids 1 1006.
• Using vmbr0.1006 with vlan-id 1006 and vlan-raw-device vmbr0.
• Verified with bridge vlan show that VLAN 1006 was not present until I added it manually.
• Switch port is trunk, VLAN 1 native, VLAN 1006 tagged.


Any advice or working configuration examples would be very much appreciated.

Thanks in advance!
 
You only need to add one IP address in the /etc/network/interfaces file. Here is my /etc/network/interfaces file from one of my nodes. Also I think you are missing a few parameters: bridge-vlan-aware yes and bridge-vids 2-4092

You should only need an IP for the management interface. All the other traffic can usually be set in the settings for each VM or CT. If you want to add a second IP address it probably needs to be on a different bridge, ie, vmrb1.1006, not vmbr0.1006. OR, you need to break out your IP address from the VMBR0 definition then create multiple virtual NICs


Code: 
auto lo
iface lo inet loopback

iface enp3s0 inet manual

auto vmbr0.100
iface vmbr0.100 inet static
        address 10.10.10.4/24
        gateway 10.10.10.1

auto vmbr0
iface vmbr0 inet static
        bridge-ports enp3s0
        bridge-stp off
        bridge-fd 0
        bridge-vlan-aware yes
        bridge-vids 2-4092

iface wlp1s0 inet manual

# source /etc/network/interfaces.d/*
 
Hi,

Thanks for the reply. I’ve followed the recommendations, but I’m still having connectivity issues. Let me explain what happens:

With this configuration, where the management IP is placed on the subinterface vmbr0.1064, the node loses connectivity:

Code: 
auto lo
iface lo inet loopback

auto eno12399np0
iface eno12399np0 inet manual

iface eno8303 inet manual
iface eno8403 inet manual

auto ens1f1np1
iface ens1f1np1 inet manual

iface eno12409np1 inet manual
iface ens1f0np0 inet manual

auto vmbr0
iface vmbr0 inet static
        bridge-ports eno12399np0
        bridge-stp off
        bridge-fd 0
        bridge-vlan-aware yes
        bridge-vids 2-4094
        bridge-pvid 1

auto vmbr0.1064
iface vmbr0.1064 inet static
        address 10.10.64.62/24
        gateway 10.10.64.13

source /etc/network/interfaces.d/*

To recover connectivity, I need to assign the IP directly to vmbr0 instead of vmbr0.1064:

Code: 
auto lo
iface lo inet loopback

auto eno12399np0
iface eno12399np0 inet manual

iface eno8303 inet manual
iface eno8403 inet manual

auto ens1f1np1
iface ens1f1np1 inet manual

iface eno12409np1 inet manual
iface ens1f0np0 inet manual

auto vmbr0
iface vmbr0 inet static
        address 10.10.64.62/24
        gateway 10.10.64.13
        bridge-ports eno12399np0
        bridge-stp off
        bridge-fd 0
        bridge-vlan-aware yes
        bridge-vids 2-4094
        bridge-pvid 1

source /etc/network/interfaces.d/*


There is only one cable connected between the server and the switch, so all traffic should be going through that link.


Thanks in advance.
 
You can't shouldn't use PVID 1. In your first example you are telling the machine to put vmbr0 on a specific VLAN, the management vlan. Then you are trying to put your management interface on a different VLAN. That won't work. Try this instead:


Code: 
auto lo
iface lo inet loopback

iface eno12399np0 inet manual
iface eno8303 inet manual
iface eno8403 inet manual
iface ens1f1np1 inet manual
iface eno12409np1 inet manual
iface ens1f0np0 inet manual

auto vmbr0
iface vmbr0 inet static
        bridge-ports eno12399np0
        bridge-stp off
        bridge-fd 0
        bridge-vlan-aware yes
        bridge-vids 2-4094

auto vmbr0.1064
iface vmbr0.1064 inet static
        address 10.10.64.62/24
        gateway 10.10.64.13

source /etc/network/interfaces.d/*
 
Hi,

I’ve managed to add the 10.10.106.0 network successfully, but I’ve noticed something strange. Once I add it, the Proxmox web interface automatically switches over and becomes accessible through the 10.10.106.152 IP instead of staying on the management IP (10.10.64.62).

Do you know why this happens, and if there’s a way to keep the web GUI bound only to the management network?

Code: 
auto lo
iface lo inet loopback

auto eno12399np0
iface eno12399np0 inet manual

auto eno8303
iface eno8303 inet manual

auto eno8403
iface eno8403 inet manual

auto ens1f1np1
iface ens1f1np1 inet manual

auto eno12409np1
iface eno12409np1 inet manual

auto ens1f0np0
iface ens1f0np0 inet manual

auto bond0
iface bond0 inet static
        address 10.10.64.62/24
        gateway 10.10.64.13
        bond-slaves eno12399np0 ens1f0np0
        bond-miimon 100
        bond-mode balance-rr

auto vmbr0
iface vmbr0 inet manual
        bridge-ports eno12409np1
        bridge-stp off
        bridge-fd 0
        bridge-vlan-aware yes
        bridge-vids 2-4094

auto vmbr0.1006
iface vmbr0.1006 inet static
        address 10.10.106.152/24

source /etc/network/interfaces.d/*

Thanks!
 
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