Proxmox 8.1.4: No traffic through vmbr0

[TomTheOne]

Hi all

I'm testing a proxmox installation out of the box and stuck with connectivity from a (any?) virtual guest to my local network.

I have following setup.

           [Internet]
                |
       [Gateway (10.0.0.254)]       [Management Station (10.0.0.100)]
                |                              |
    ------ LAN (10.0.0.0/24) ---------------------
                |
       [Proxmox (10.0.0.81)]
                |
      [Windows VM (10.0.0.85)]

The interfaces config on the Proxmox (10.0.0.81) looks like this.

cat /etc/network/interfaces

# network interface settings; autogenerated
# Please do NOT modify this file directly, unless you know what
# you're doing.
#
# If you want to manage parts of the network configuration manually,
# please utilize the 'source' or 'source-directory' directives to do
# so.
# PVE will preserve these directives, but will NOT read its network
# configuration from sourced files, so do not attempt to move any of
# the PVE managed interfaces into external files!

auto lo
iface lo inet loopback

auto ens160
iface ens160 inet manual

auto ens192
iface ens192 inet manual

auto vmbr0
iface vmbr0 inet manual
        address 10.0.0.81/24
        gateway 10.0.0.254
        bridge-ports ens160
        bridge-stp off
        bridge-fd 0


source /etc/network/interfaces.d/*

I would like to become able to reach the virtual Windows vm (10.0.0.85) from the LAN (10.0.0.0/24) and vice-versa.

- The management station can reach vmbr0 (10.0.0.81), but i can not reach the virtual Windows vm (10.0.0.85).
- The windows vm can reach vmbr0 (10.0.0.81), but can not reach the gateway (10.0.0.254) and anything in LAN (10.0.0.0/24).
- The proxmox host (10.0.0.81) can reach the virtual Windows vm (10.0.0.85) and can reach the gateway (10.0.0.254).

Already tried:
- I tried to uncomment "net.ipv4.ip_forward=1" in "/etc/sysctl.conf" followed by a reboot, but no change.

Thanks for reading. If you have any input please let me know.

Best regards
- Tom

 

[TomTheOne]

Hi all

In meantime i found the root cause; the proxmox host is a virtual host on a vmware farm and is not installed bare metal.

This requires a configuration on the vmware's vSwitch.

The issue was solved after following change was made.

-> Edit the config of the affected vSwitch (vSwitch0 in this case) and allow at register "Security":

- Promiscous mode
- MAC address changes
- Forged transmits



Hint: This change will interrupt network connectivity to all hosts on this vSwitch for a few seconds.

Regards
- Tom

 

[Biidouille]

Thank you for posting the answer, I just had the same issue

For a bit more explanation : the vswitch in ESXi do not allow more than 1 mac address on each "port" by default. But if you have your proxmox VM in bridge with the proxmox interface, you have multiple machines, and so multiple mac, on the same vswitch port. Vmware will shut it down.
Removing the security parameters show in the answer above solve this.

Again, thank you so much ! I would'nt have think about this without seeing your post !

 

[_gabriel]

ESXi do not allow more than 1 mac address on each "port" by default

Like other hypervisor.
For Proxmox, turning off MAC Filter is required.