1500 MTU on vlan-aware bridge where VLANs need to use 9000 MTU?

Dunuin

Distinguished Member
Jun 30, 2020
14,764
4,496
258
Germany
Hi,

Lets say my network config now looks like this...
Code:
auto lo
iface lo inet loopback

iface eno1 inet manual
        mtu 9000

auto vmbr0
iface vmbr0 inet manual
        address  10.0.0.2/24
        gateway  10.0.0.1
        bridge-ports eno1
        bridge-stp off
        bridge-fd 0
        bridge-vlan-aware yes
        bridge-vids 2-4094
        mtu 9000

auto vmbr0.10
iface vmbr0.10 inet static
        address  10.0.10.2/24
        mtu 9000
...because PBS and other stuff on VLAN10 should be using an MTU of 9000 for better performance.
Setting MTU 9000 on vmbr0.10 requires vmbr0 + eno1 to be using a 9000 MTU as well.
What would I do if I wanted PVE to be using an MTU of 1500 on the 10.0.0.0/24 subnet of vmbr0 for gateway access as well as management?
Putting the management/gateway on another VLAN interface like "vmbr0.1" with an MTU of 1500 would work but I want those packets to be untagged.
 
you need to set your bridge port and then change the MTU to 1500 if you want to attach it to VM's or containers else configure it as a vlan

Bridge
Code:
auto special
iface special inet static
        address  10.0.10.2/24
        bridge-ports vmbr0.10
        bridge-stp off
        bridge-fd 0
        mtu 1500

VLAN
Code:
auto special
iface special inet static
    address 10.10.10.10/24
    vlan-id 10
    vlan-raw-device vmbr0
    mtu 1500
 
Last edited:
Hi,

Lets say my network config now looks like this...
Code:
auto lo
iface lo inet loopback

iface eno1 inet manual
        mtu 9000

auto vmbr0
iface vmbr0 inet manual
        address  10.0.0.2/24
        gateway  10.0.0.1
        bridge-ports eno1
        bridge-stp off
        bridge-fd 0
        bridge-vlan-aware yes
        bridge-vids 2-4094
        mtu 9000

auto vmbr0.10
iface vmbr0.10 inet static
        address  10.0.10.2/24
        mtu 9000
...because PBS and other stuff on VLAN10 should be using an MTU of 9000 for better performance.
Setting MTU 9000 on vmbr0.10 requires vmbr0 + eno1 to be using a 9000 MTU as well.
What would I do if I wanted PVE to be using an MTU of 1500 on the 10.0.0.0/24 subnet of vmbr0 for gateway access as well as management?
Putting the management/gateway on another VLAN interface like "vmbr0.1" with an MTU of 1500 would work but I want those packets to be untagged.
use differents vlan (vmbr0.X), with differents mtu. (but keep vmbr0 at mtu 9000). This is the only way.
 

About

The Proxmox community has been around for many years and offers help and support for Proxmox VE, Proxmox Backup Server, and Proxmox Mail Gateway.
We think our community is one of the best thanks to people like you!

Get your subscription!

The Proxmox team works very hard to make sure you are running the best software and getting stable updates and security enhancements, as well as quick enterprise support. Tens of thousands of happy customers have a Proxmox subscription. Get yours easily in our online shop.

Buy now!