[SOLVED] Nested hypervisor networking issues - no traffic passing

[GivenLoud]

I'm another vmware admin who's looking at Proxmox as a potential transition option. I'm not doing anything particularly intensive, I just deployed a few hypervisor VMs (under ESXi) to get a feel for the system, deploying VMs, networking, etc.

Everything is working fine so far, other than the networking - I can't get any of the clients that I build inside of Proxmox to see my network. I have both a Windows 11 and an Ubuntu 20.x Desktop VM and they're both having the same issue - the NIC is up and configured correctly, but neither can get a DHCP address and setting a static IP doesn't do it.

My setup is Server > vSphere 8x > Proxmox 8.14 (VM) > Client VM.

The Ptoxmox host has an IP address and works as intended, I am able to manage the storage and everything else. It's just the networking that's the issue and I'm thinking perhaps it's the extra bridge?

I have all of the firewalls disabled in the Proxmos datacenter and I've tried different network card hardware types inside of the VMs themselves and it makes no difference. The clients can see the NICs, the traffic just isn't getting anywhere.

vmbr0 is the "Linux Bridge" in proxmox, the UI says its active and has a CIDR address that matches the hypervisor. The network card on the client VM says it's assigned to bridge vmbr0 as well.I grabbed the Virtual IO driver ISO and installed all of them into the WIndows client, but that solve it.

Any insight as to what I might be missing would be appreciated! Everything is about as default as I can get it, all I've done is give the Proxmox hypervisor an IP address, build a couple of fresh VMs and that's it.

Thanks!

 

[GivenLoud]

/etc/network/interfaces from the Proxmox VM:

auto lo
iface lo inet loopback

iface ens192 inet manual

auto vmbr0
iiface vmbr0 inet static
address proxmox.ip.address/24
gateway my.gateway.address
bridge-ports ens192
bridge-stp off
bridge-fd 0

source /etc/network/interfaces.d/*

under Datacenter > My Proxmox > Network:

Name: vmbr0
Type: Linux Bridge
Active: Yes
Autostart: Yes
VLAN aware: Yes (have also tried setting this to no)
Ports/Slaves: ens192
CIDR: Proxmox host IP same as above
Gateway: Same IP as above

 

[leesteken]

iface ens291 inet manual

does not match with

bridge-ports ens192

But then you would not be able to use the Proxmox web GUI. Maybe show the real output of cat /etc/network/interfaces and ip a?

EDIT: The actual problem is probably the network setup for the VM inside ESXi. Is it bridged without a firewall and are you sure DHCP requests are able to reach the DHCP server (and back)?

 

[GivenLoud]

does not match with

But then you would not be able to use the Proxmox web GUI. Maybe show the real output of cat /etc/network/interfaces and ip a?

Argh, sorry about that - typo. I'm playing inception with console windows so I typed that out manually.

They are correctly ens192 in both.

 

[GivenLoud]

Update: This was a vmware thing, not a Proxmox thing. I had promiscuous mode enabled on the vswitch, but not forged transits.

If anyone else comes across this in a search - for nested hypervisors you need both of those enabled.

 

[leesteken]

Update: This was a vmware thing, not a Proxmox thing. I had promiscuous mode enabled on the vswitch, but not forged transits.

If anyone else comes across this in a search - for nested hypervisors you need both of those enabled.

If you edit your first post in this thread and select Solved from the pull-down menu, people might find it easier to find this solution.