Proxmox 9.1 and vlans stopped working.

J

jalbrizio

New Member
Nov 10, 2025
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Hello proxmox community, does anyone have any info on getting trunked vlans working in 9.1? Here is my issue:
I installed proxmox 9.1 everything went smoothly with the install. This is on a dell server with multiple nics, all on vlans and the primary access is on a trunk port. The installer does not support an install with access on a trunk port. This was expected as it has never worked out of the box. I then rebooted and I went to set up the nics with vlans. I edited the interfaces file to get some of it working.
The other issue is when I went to set up the nics with trunk ports.
I could get one vlan working if I created a nic alias using nic1.[vlannumber] . If I add another vlan on the same nic using nic1.[vlannumber2] the second vlan does not work. Additionally, I am not able to create a working bridge for the vms to use the vlans. This was enough to get me into the web gui so I hopped in and tried to do some of the config in the gui.
Nothing worked vlan related in the web gui so I gave up and worked in the interfaces file.
I was unable to get the trunked nics working properly. The nics that are connected to access ports with one vlan set up came online, but only one would work at a time if they where on the same network so I would not be able to get multipathing working.

I ended up reinstalling with proxmox9.0 to get everything working as expected.
 
Nothing has changed regarding this afaik. You need switchport with multiple vlans on it (vlan trunk), then create a vmbr0 with a bridged port (that connects to your switchport that(s) with the vlans on it). Then USE the sdn, as its the most simple way to do vlans for vm-access. If you also want a tagged vlan for mangement, create a vmbr0.VLAN-ID with the ip of mgmt on it.

Edit: post your 9.1 network-config and people might take a look at and help.
 
Last edited:
jsterr said:
Nothing has changed regarding this afaik. You need switchport with multiple vlans on it (vlan trunk), then create a vmbr0 with a bridged port (that connects to your switchport that(s) with the vlans on it). Then USE the sdn, as its the most simple way to do vlans for vm-access. If you also want a tagged vlan for mangement, create a vmbr0.VLAN-ID with the ip of mgmt on it.

Edit: post your 9.1 network-config and people might take a look at and help.
Click to expand...

Thank you for the reply. That is how I have it set up.

This works with a fresh install of 9.0 but not a fresh install of 9.1

my config is as follows"

auto lo
iface lo inet loopback

iface ens1f0np0 inet manual
mtu 9000

iface ens1f1np1 inet manual

iface ens2f0np0 inet manual

iface ens2f1np1 inet manual
mtu 9000

iface eno3 inet manual

iface eno4 inet manual

iface eno1 inet manual

iface eno2 inet manual

auto vmnetwork0
iface vmnetwork0 inet manual
bridge-ports ens1f1np1
bridge-stp off
bridge-fd 0
bridge-vlan-aware yes
bridge-vids 50 55 60 70 75 80 85 90 95 100 105 110 115 120 125 130

auto vmnetwork1
iface vmnetwork1 inet manual
bridge-ports ens2f0np0
bridge-stp off
bridge-fd 0
bridge-vlan-aware yes
bridge-vids 50 55 60 70 75 80 85 90 95 100 105 110 115 120 125 130

auto vmbr65
iface vmbr65 inet static
address 192.168.2.4/24
bridge-ports ens1f0np0
bridge-stp off
bridge-fd 0
bridge-vlan-aware yes
bridge-vids 65
mtu 9000

auto vmbr651
iface vmbr651 inet static
address 192.168.2.3/24
bridge-ports ens2f1np1
bridge-stp off
bridge-fd 0
bridge-vlan-aware yes
bridge-vids 65
mtu 9000

auto vlan100
iface vlan100 inet static
address 192.168.1.11/24
gateway 192.168.1.1
vlan-raw-device vmnetwork1

source /etc/network/interfaces.d/*

ens1f0np0 and ens2f1np1 are on 2 different switches connected to the san. the ports are setup as access.
ens1f1np1 and ens2f0np0 are on 2 different switches with multiple vlans. the ports are setup as trunk ports with all of the vlans available on the trunk.

This setup only works on 9.0 but not 9.1

When I installed 9.1 I can get one network device working if I create a vlan differently using the following:

#This creates the vlan interface differently than 9.0
iface ens1f1np1.100 inet manual

then I use

auto vmbr0
iface vmbr0 inet static
address 192.168.1.12/24
gateway 192.168.1.1
bridge-ports ens1f1np1.100

If I try to add another vlan using

iface ens1f1np1.105 inet manual
auto vmbr1
iface vmbr1 inet static
address 192.168.1.13/24
gateway 192.168.1.1
bridge-ports ens1f1np1.105

This second vlan does not work.
jsterr said:
Nothing has changed regarding this afaik. You need switchport with multiple vlans on it (vlan trunk), then create a vmbr0 with a bridged port (that connects to your switchport that(s) with the vlans on it). Then USE the sdn, as its the most simple way to do vlans for vm-access. If you also want a tagged vlan for mangement, create a vmbr0.VLAN-ID with the ip of mgmt on it.

Edit: post your 9.1 network-config and people might take a look at and help.
Click to expand...
 
jalbrizio said:
Thank you for the reply. That is how I have it set up.

This works with a fresh install of 9.0 but not a fresh install of 9.1

my config is as follows"

auto lo
iface lo inet loopback

iface ens1f0np0 inet manual
mtu 9000

iface ens1f1np1 inet manual

iface ens2f0np0 inet manual

iface ens2f1np1 inet manual
mtu 9000

iface eno3 inet manual

iface eno4 inet manual

iface eno1 inet manual

iface eno2 inet manual

auto vmnetwork0
iface vmnetwork0 inet manual
bridge-ports ens1f1np1
bridge-stp off
bridge-fd 0
bridge-vlan-aware yes
bridge-vids 50 55 60 70 75 80 85 90 95 100 105 110 115 120 125 130

auto vmnetwork1
iface vmnetwork1 inet manual
bridge-ports ens2f0np0
bridge-stp off
bridge-fd 0
bridge-vlan-aware yes
bridge-vids 50 55 60 70 75 80 85 90 95 100 105 110 115 120 125 130

auto vmbr65
iface vmbr65 inet static
address 192.168.2.4/24
bridge-ports ens1f0np0
bridge-stp off
bridge-fd 0
bridge-vlan-aware yes
bridge-vids 65
mtu 9000

auto vmbr651
iface vmbr651 inet static
address 192.168.2.3/24
bridge-ports ens2f1np1
bridge-stp off
bridge-fd 0
bridge-vlan-aware yes
bridge-vids 65
mtu 9000

auto vlan100
iface vlan100 inet static
address 192.168.1.11/24
gateway 192.168.1.1
vlan-raw-device vmnetwork1

source /etc/network/interfaces.d/*

ens1f0np0 and ens2f1np1 are on 2 different switches connected to the san. the ports are setup as access.
ens1f1np1 and ens2f0np0 are on 2 different switches with multiple vlans. the ports are setup as trunk ports with all of the vlans available on the trunk.

This setup only works on 9.0 but not 9.1

When I installed 9.1 I can get one network device working if I create a vlan differently using the following:

#This creates the vlan interface differently than 9.0
iface ens1f1np1.100 inet manual

then I use

auto vmbr0
iface vmbr0 inet static
address 192.168.1.12/24
gateway 192.168.1.1
bridge-ports ens1f1np1.100

If I try to add another vlan using

iface ens1f1np1.105 inet manual
auto vmbr1
iface vmbr1 inet static
address 192.168.1.13/24
gateway 192.168.1.1
bridge-ports ens1f1np1.105

This second vlan does not work.
Click to expand...

Also, I just tested and if I have a 9.0 server setup this way and I and I upgrade using

apt-get update
apt-get upgrade
apt update
apt dist-upgrade

This gets me to 9.1.5 and my servers continue to work fine after this.
This seems to only be an issue with a fresh install of 9.1
 
Last edited:
I am also having this issue, fresh install of 9.1 today even after upgrading via apt to 9.1.5, any of my Tagged vms dont work. im coming off a hardware failure and 3 installs so im hoping to find a fix that doesn't include a 4th install of 9.0 and then upgrading back. I have a lot of VMs, restoring backups is annoying and all my stuff is down
 
ticnitsi said:
I am also having this issue, fresh install of 9.1 today even after upgrading via apt to 9.1.5, any of my Tagged vms dont work
Click to expand...
Did you reboot the node after the upgrade?

Otherwise, can you post your network configuration?

Code: 
cat /etc/network/interfaces
cat /etc/network/interfaces.d/sdn

ip a

Plus the config of a VM that isn't working?

Code: 
qm config <VMID>
 
ticnitsi said:
I am also having this issue, fresh install of 9.1 today even after upgrading via apt to 9.1.5, any of my Tagged vms dont work. im coming off a hardware failure and 3 installs so im hoping to find a fix that doesn't include a 4th install of 9.0 and then upgrading back. I have a lot of VMs, restoring backups is annoying and all my stuff is down
Click to expand...

So far installing 9.0 and upgrading to 9.1 is the only fix that I found for the issue.
I also had to run through the install 4 times then get my vms online. It looks like the 9.1 install is is either broken or there are new settings that need to be worked out by proxmox. Either way, the iso should probably be rolled back and redeployed with a fix.
 
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jalbrizio said:
So far installing 9.0 and upgrading to 9.1 is the only fix that I found for the issue.
I also had to run through the install 4 times then get my vms online. It looks like the 9.1 install is is either broken or there are new settings that need to be worked out by proxmox. Either way, the iso should probably be rolled back and redeployed with a fix.
Click to expand...
Yeah, after the hell I had restoring my system after crash, im not looking forward to doing it again
 
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slavik-f said:
If I run `apt dist-upgrade` - will that apply these commits?
I'm using Proxmox `No-subscription` repository.
Click to expand...
Yes, they are contained in the newer packages. You might need to either restart the node afterwards or migrate the VMs away, do the upgrade, then migrate them back. If you are using SDN, then the configuration needs to be re-applied as well in case you are using VLANs in conjunction with bonds.
 
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