Virtualbox nested VM networking

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discoverix558
Posts: 2
Joined: 7. May 2022, 13:54

Virtualbox nested VM networking

Post by discoverix558 »

For testing and prototyping purposes I want to use a nested VM environment on a local machine (Ryzen 7) and in Virtualbox (6.1.34) with L0 (host), L1 (guest), L2 (guest-guest). L0 is a Windows 10 host, L1 a Virtualbox guest with Ubuntu 20.04 LTS server (no GUI), L2 an Ubuntu 20.04 LTS server guest on a kvm/qemu hypervisor on L1. I have set up network bridges from L0 to L1 and from L1 to L2 with free and fixed ip addresses in the address range of my host (L0) network. All machines have distinct mac addresses.

All machines work fine and I can now ssh from L0 into L1 and from L1 into L2, however I have no network connection from L0 to L2 and vice versa. That is what I am looking for in order to update L2 from the internet and to use L2 as a server. I may be that my bridge networking setup is not suitable for the purpose or that there is just missing some „glue“ between L0 and L2.
Does anyone have a suggestion how to resolve this problem or where to find further documentation for a workable setup ? I have cockpit installed on L1 and could use that for additional network configurations if that would help.
fth0
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Re: Virtualbox nested VM networking

Post by fth0 »

An educated guess: Did you allow Promiscuous Mode in the VirtualBox VM's network settings?

Other than that, please describe in more detail what you mean with the term "bridg...". Note that there can be slight differences in bridging when you look at Linux, VirtualBox, QEMU and Docker.
discoverix558
Posts: 2
Joined: 7. May 2022, 13:54

Re: Virtualbox nested VM networking

Post by discoverix558 »

Hi fth0,
the promiscuous mode - a switch I hardly noticed before - was set to "deny". I changed it to "allow for all VMs and host" in the virtualbox L1 network settings and now everything works fine, L2 has internet access and can be accessed from L0. Thanks a lot for your help.
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